Chapter III

THE RAINFALL OF THE WESTERN PORTION OF THE UNITED STATES.

The Smithsonian Institution conducted for a number of years an extensive system of measurements of rainfall in the United States, and at the same time diligently collected pluvial records from every possible source. The accumulated data thus collected were placed in the hands of Mr. Charles A. Schott for reduction and discussion, and he prepared the “Smithsonian Tables of Precipitation in Rain and Snow”, which appeared in 1868. Since that time much additional material has been acquired by the continuation of the work to the present time, and also by a great increase in the number of observation stations, and so valuable is this new material that it has been determined to recompile the tables and issue a second edition. By the time the present report was called for, the preliminary computations for the tables had developed an important body of facts bearing on the climate of the Arid Region, and through the courtesy of Prof. Joseph Henry, Secretary of the Smithsonian Institution, and of Mr. Schott, they were placed at my disposal. Mr. Schott also made such a change in the order of computation as to give precedence to the states and territories which form the subject of this investigation, and by this timely favor made it possible to base the following discussion on the very latest determinations of rainfall.

The results thus made available exhibit the mean precipitation at each station of observation west of the Mississippi River for each month, for each season, and for the year. A number of other data are also tabulated, including the latitude, longitude, and altitude of each station, and the extent of each series of observations in years and months. In selecting material for the present purpose the shorter records were ignored. The variations from year to year are so great that an isolated record of a single year is of no value as an indication of the average rainfall. The mean of two or three years is almost equally liable to mislead, and only a long series of observations can afford accurate results. In the following tables no stations are included (with one exception) which show records of less than five years’ extent.

Table I shows the precipitation of the Sub-humid Region; Table II, of the Arid Region; Table III, of the San Francisco Region; and Table IV, of the Region of the Lower Columbia. The limits of each region have been given in a former chapter, and need not be repeated. In each table the first column contains the names of the stations of observation; the second, their latitudes; the third, their longitudes (west from Greenwich); and the fourth, their altitudes in feet above the level of the sea. The next four columns show for each season of the year the mean observed rainfall in inches, and their sum appears in the following column as the mean yearly rainfall. In the last column the extent of each series of observations is given in years and months. In Table I the stations are arranged by latitudes, in Tables II, III, and IV, alphabetically.

TABLE I.--_Precipitation of Sub-humid Region._

+----------------------+----------+-----------+--------+ | Station. | Latitude.| Longitude.| Height.| +----------------------+----------+-----------+--------+ | | ° ´ | ° ´ | Feet. | |Pembina, Dak | 48 57 | 97 03 | 768 | |Fort Totten, Dak | 47 56 | 99 16 | 1,480 | |Fort Abercrombie, Dak | 46 27 | 96 21 | -- | |Fort Wadsworth, Dak | 45 43 | 97 10 | 1,650 | |Omaha Agency, Nebr | 42 07 | 96 22 | -- | |Fort Kearney, Nebr | 40 38 | 98 57 | 2,360 | |Fort Riley, Kans | 39 03 | 96 35 | 1,300 | |Fort Hays, Kans | 38 59 | 99 20 | 2,107 | |Fort Larned, Kans | 38 10 | 98 57 | 1,932 | |Fort Belknap, Tex | 33 08 | 98 46 | 1,600 | |Fort Griffin, Tex | 32 54 | 99 14 | -- | |Fort Chadbourne, Tex | 31 58 |100 15 | 2,020 | |Fort McKavett, Tex | 30 48 |100 08 | 2,060 | |New Braunfels, Tex | 29 42 | 98 15 | 720 | |Fort Clark, Tex | 29 17 |100 25 | 1,000 | |Fort Inge, Tex | 29 10 | 99 50 | 845 | |Fort Duncan, Tex | 28 39 |100 30 | 1,460 | |Fort Brown, Tex | 25 50 | 97 37 | 50 | +----------------------+----------+-----------+--------+

+----------------------+--------------------------------------+-------+ | | Mean precipitation, in inches. |Extent | | +-------+-------+-------+-------+------+ of | | Station. |Spring.|Summer.|Autumn.|Winter.| Year.|record.| +----------------------+-------+-------+-------+-------+------+-------+ | | | | | | | Y. M.| |Pembina, Dak | 4.02 | 7.24 | 2.71 | 1.53 | 15.50| 4 8 | |Fort Totten, Dak | 5.18 | 7.17 | 2.50 | 1.59 | 16.44| 5 5 | |Fort Abercrombie, Dak | 4.80 | 8.67 | 3.46 | 1.85 | 18.78| 13 6 | |Fort Wadsworth, Dak | 7.00 | 10.25 | 3.98 | 2.92 | 24.15| 6 5 | |Omaha Agency, Nebr | 8.21 | 8.70 | 5.77 | 2.90 | 25.58| 5 2 | |Fort Kearney, Nebr | 7.81 | 11.13 | 4.83 | 1.45 | 25.22| 14 4 | |Fort Riley, Kans | 5.49 | 10.48 | 5.92 | 2.63 | 24.52| 20 10 | |Fort Hays, Kans | 6.93 | 6.23 | 5.77 | 3.77 | 22.70| 6 11 | |Fort Larned, Kans | 5.17 | 9.63 | 4.95 | 1.67 | 21.42| 10 9 | |Fort Belknap, Tex | 6.41 | 9.44 | 8.34 | 3.86 | 28.05| 5 10 | |Fort Griffin, Tex | 4.95 | 6.25 | 6.14 | 4.17 | 21.51| 5 3 | |Fort Chadbourne, Tex | 5.77 | 6.53 | 7.06 | 3.52 | 22.88| 8 7 | |Fort McKavett, Tex | 5.21 | 6.71 | 7.81 | 4.22 | 23.95| 9 7 | |New Braunfels, Tex | 7.60 | 6.90 | 8.83 | 4.25 | 27.58| 5 1 | |Fort Clark, Tex | 4.14 | 7.57 | 6.55 | 4.35 | 22.61| 12 5 | |Fort Inge, Tex | 5.38 | 9.67 | 6.88 | 3.53 | 25.46| 7 4 | |Fort Duncan, Tex | 3.56 | 8.60 | 6.54 | 2.63 | 21.33| 11 7 | |Fort Brown, Tex | 3.18 | 7.64 | 13.02 | 4.04 | 27.88| 15 0 | +----------------------+-------+-------+-------+-------+------+-------+

TABLE II.--_Precipitation of the Arid Region._

+---------------------------------------------------+ | |Latitude. | | | |Longitude. | | | | |Height.| | Station. | | | | | | | | | +----------------------------+------+-------+-------+ | | ° ´ | ° ´ | Feet. | |Albuquerque, N. Mex |35 06 |106 38 | 5,032 | |Camp Bowie, Ariz |32 10 |109 30 | 4,872 | |Camp Douglas, Utah |40 46 |111 50 | 5,024 | |Camp Grant, Ariz |32 54 |110 40 | 4,833 | |Camp Halleck, Nev |40 49 |115 20 | 5,790 | |Camp Harney, Oreg |43 00 |119 00 | -- | |Camp Independence, Cal |36 50 |118 11 | 4,800 | |Camp McDermitt, Nev |41 58 |117 40 | 4,700 | |Camp McDowell, Ariz |33 46 |111 36 | -- | |Camp Mohave, Ariz |35 02 |114 36 | 604 | |Camp Verde, Ariz |34 34 |111 54 | 3,160 | |Camp Warner, Oreg |42 28 |119 42 | -- | |Camp Whipple, Ariz |34 27 |112 20 | 5,700 | |Cantonment Burgwin, N. Mex |36 26 |105 30 | 7,900 | |Drum Barracks, Cal |33 47 |118 17 | 32 | |Denver, Colo |39 45 |105 01 | 5,250 | |Fort Bayard, N. Mex |32 46 |108 30 | 4,450 | |Fort Benton, Mont |47 50 |110 39 | 2,730 | |Fort Bidwell, Cal |41 50 |120 10 | 4,680 | |Fort Bliss (El Paso), Tex |31 47 |106 30 | 3,830 | |Fort Boisé, Idaho |43 40 |116 00 | 1,998 | |Fort Bridger, Wyo |41 20 |110 23 | 6,656 | |Fort Buford, Dak |48 01 |103 58 | 1,900 | |Fort Colville, Wash |48 42 |118 02 | 1,963 | |Fort Craig, N. Mex |33 38 |107 00 | 4,619 | |Fort D. A. Russell, Wyo |41 12 |104 50 | -- | |Fort Davis, Tex |30 40 |104 07 | 4,700 | |Fort Defiance, Ariz |35 43 |109 10 | 6,500 | |Fort Fetterman, Wyo |42 50 |105 29 | 4,973 | |Fort Fillmore, N. Mex |32 14 |106 42 | 3,937 | |Fort F. Steele, Wyo |41 47 |106 57 | 6,841 | |Fort Garland, Colo |37 25 |105 40 | 7,864 | |Fort Lapwai, Idaho |46 18 |116 54 | 2,000 | |Fort Laramie, Wyo |42 12 |104 31 | 4,472 | |Fort Lyon, Colo |38 08 |102 05 | 4,000 | |Fort Massachusetts, Colo |37 32 |105 23 | 8,365 | |Fort McPherson, Nebr |41 00 |100 30 | 3,726 | |Fort McIntosh, Tex |27 35 | 99 48 | 806 | |Fort McRae, N. Mex |33 18 |107 03 | 4,500 | |Fort Randall, Dak |43 01 | 98 37 | 1,245 | |Fort Rice, Dak |46 32 |100 33 | -- | |Fort Sanders, Wyo |41 17 |105 36 | 7,161 | |Fort Selden, N. Mex |32 23 |106 55 | -- | |Fort Shaw, Mont |47 30 |111 42 | 6,000 | |Fort Stanton, N. Mex |33 29 |105 38 | 5,000 | |Fort Stevenson, Dak |47 36 |101 10 | -- | |Fort Stockton, Tex |30 20 |102 30 | 4,950 | |Fort Sully, Dak |44 50 |100 35 | 1,672 | |Fort Union, N. Mex |35 54 |104 57 | 6,670 | |Fort Walla Walla, Wash |46 03 |118 20 | 800 | |Fort Wingate, N. Mex |35 29 |107 45 | 6,982 | |Fort Yuma, Cal |32 44 |114 36 | 200 | |Ringgold Barracks, Tex |26 23 | 99 00 | 521 | |Salt Lake City, Utah |40 46 |111 54 | 4,534 | |San Diego, Cal |32 42 |117 14 | 150 | |Santa Fé, N. Mex |35 41 |106 02 | 6,846 | +----------------------------+------+-------+-------+

+----------------------------+------------------------------+-------+ | | Mean precipitation, | | | | in inches. | | | +------------------------------+ | | |Spring. | | | | |Summer. |Extent | | | | |Autumn. | of | | Station. | | | |Winter. |record.| | | | | | |Year. | | +----------------------------+-----+-----+----+------+------+-------+ | | | | | | | Y. M.| |Albuquerque, N. Mex | 0.83| 4.35|2.04| 0.89 | 8.11 | 12 2| |Camp Bowie, Ariz | 1.29| 7.35|2.03| 4.59 |15.26 | 6 8| |Camp Douglas, Utah | 7.20| 2.18|3.24| 6.20 |18.82 | 10 3| |Camp Grant, Ariz | 2.08| 6.25|3.27| 3.48 |15.08 | 6 10| |Camp Halleck, Nev | 3.66| 1.19|2.31| 3.82 |10.98 | 5 8| |Camp Harney, Oreg | 2.29| 1.09|1.59| 3.79 | 8.76 | 6 0| |Camp Independence, Cal | 1.09| 0.35|0.62| 4.54 | 6.60 | 8 2| |Camp McDermitt, Nev | 3.02| 0.72|1.13| 3.66 | 8.53 | 6 4| |Camp McDowell, Ariz | 1.11| 4.79|1.73| 3.82 |11.45 | 8 2| |Camp Mohave, Ariz | 0.81| 1.27|0.93| 1.64 | 4.65 | 9 1| |Camp Verde, Ariz | 1.25| 4.65|2.41| 2.54 |10.85 | 6 1| |Camp Warner, Oreg | 4.31| 1.10|2.53| 6.47 |14.41 | 5 3| |Camp Whipple, Ariz | 3.88| 8.07|2.15| 5.18 |19.28 | 7 5| |Cantonment Burgwin, N. Mex | 1.57| 2.92|2.42| 1.74 | 8.65 | 5 9| |Drum Barracks, Cal | 2.26| 0.26|0.35| 5.87 | 8.74 | 5 5| |Denver, Colo | 5.02| 3.69|3.16| 1.90 |13.77 | 5 1| |Fort Bayard, N. Mex | 1.54| 7.22|2.28| 3.28 |14.32 | 7 6| |Fort Benton, Mont | 5.34| 4.48|1.65| 1.79 |13.26 | 7 1| |Fort Bidwell, Cal | 4.95| 1.54|3.03|10.71 |20.23 | 8 3| |Fort Bliss (El Paso), Tex | 0.43| 3.49|3.38| 1.23 | 8.53 | 14 3| |Fort Boisé, Idaho | 5.16| 1.15|2.50| 6.67 |15.48 | 9 5| |Fort Bridger, Wyo | 2.99| 2.05|1.68| 1.71 | 8.43 | 12 10| |Fort Buford, Dak | 3.76| 4.06|2.01| 2.01 |11.84 | 7 10| |Fort Colville, Wash | 3.63| 3.04|2.56| 4.83 |14.06 | 11 0| |Fort Craig, N. Mex | 0.70| 5.87|3.43| 1.06 |11.06 | 15 9| |Fort D. A. Russell, Wyo | 4.76| 4.56|3.27| 1.50 |14.09 | 5 1| |Fort Davis, Tex | 1.84| 8.76|4.72| 1.80 |17.12 | 8 11| |Fort Defiance, Ariz | 2.03| 5.91|3.72| 2.55 |14.21 | 8 5| |Fort Fetterman, Wyo | 4.48| 4.12|2.99| 3.51 |15.10 | 5 7| |Fort Fillmore, N. Mex | 0.48| 4.16|3.02| 0.76 | 8.42 | 8 3| |Fort F. Steele, Wyo | 4.57| 3.48|3.05| 4.28 |15.38 | 5 5| |Fort Garland, Colo | 3.28| 6.70|2.37| 2.51 |14.86 | 13 1| |Fort Lapwai, Idaho | 4.11| 2.41|3.38| 4.99 |14.89 | 9 8| |Fort Laramie, Wyo | 5.35| 4.40|2.73| 1.97 |14.45 | 17 8| |Fort Lyon, Colo | 4.33| 5.44|2.30| 0.49 |12.56 | 7 9| |Fort Massachusetts, Colo | 3.12| 5.56|6.28| 2.27 |17.23 | 5 1| |Fort McPherson, Nebr | 6.90| 7.56|3.25| 1.25 |18.96 | 6 9| |Fort McIntosh, Tex | 3.22| 6.56|5.38| 2.35 |17.51 | 14 7| |Fort McRae, N. Mex | 2.43| 6.15|2.32| 0.69 |11.59 | 5 0| |Fort Randall, Dak | 4.72| 6.22|3.40| 1.18 |15.52 | 15 6| |Fort Rice, Dak | 3.63| 4.87|1.54| 1.35 |11.39 | 6 1| |Fort Sanders, Wyo | 3.55| 4.15|2.33| 1.43 |11.46 | 6 10| |Fort Selden, N. Mex | 0.58| 4.83|1.86| 1.22 | 8.49 | 8 5| |Fort Shaw, Mont | 2.18| 2.30|1.34| 1.13 | 6.95 | 7 3| |Fort Stanton, N. Mex | 3.03|10.61|4.86| 2.44 |20.94 | 7 9| |Fort Stevenson, Dak | 3.41| 4.97|2.15| 1.31 |11.84 | 6 2| |Fort Stockton, Tex | 1.24| 5.66|3.31| 1.29 |11.50 | 5 8| |Fort Sully, Dak | 6.52| 7.18|1.70| 1.14 |16.54 | 7 8| |Fort Union, N. Mex | 2.12|11.92|3.79| 1.32 |19.15 | 17 5| |Fort Walla Walla, Wash | 4.69| 2.07|4.98| 7.62 |19.36 | 8 8| |Fort Wingate, N. Mex | 1.96| 6.50|3.42| 5.44 |17.32 | 9 1| |Fort Yuma, Cal | 0.27| 1.30|1.36| 0.98 | 3.91 | 16 6| |Ringgold Barracks, Tex | 3.71| 7.00|6.31| 2.58 |19.60 | 14 2| |Salt Lake City, Utah | 6.25| 6.28|4.71| 7.57 |24.81 | 9 2| |San Diego, Cal | 1.89| 0.36|1.89| 5.17 | 9.31 | 24 2| |Santa Fé, N. Mex | 2.17| 6.82|3.45| 2.47 |14.91 | 19 10| +----------------------------+-----+-----+----+------+------+-------+

TABLE III.--_Precipitation of the San Francisco Region._

+---------------------------------------------------+ | |Latitude. | | | |Longitude. | | | | |Height.| | Station. | | | | | | | | | +----------------------------+------+-------+-------+ | | ° ´ | ° ´ | Feet.| |Alcatraz Island |37 49 |122 25 | -- | |Angel Island |37 51 |122 26 | 30 | |Benicia Barracks |38 03 |122 09 | 64 | |Fort Miller |37 00 |119 40 | 402 | |Fort Point |37 48 |122 29 | 27 | |Monterey |36 37 |121 52 | 40 | |Sacramento |38 34 |121 26 | 81 | |San Francisco; Presidio |37 47 |122 28 | 150 | |San Francisco |37 48 |122 25 | 130 | +----------------------------+------+-------+-------+

+----------------------------+------------------------------+-------+ | | Mean precipitation, | | | | in inches. | | | +------------------------------+ | | |Spring. | | | | |Summer. |Extent | | | | |Autumn. | of | | Station. | | | |Winter. |record.| | | | | | |Year. | | +----------------------------+-----+-----+----+------+------+-------+ | | | | | | | Y. M.| |Alcatraz Island | 2.59| 0.01|1.85|12.04 |16.49 | 9 5| |Angel Island | 3.52| 0.02|2.75|12.29 |18.58 | 5 11| |Benicia Barracks | 4.10| 0.13|2.28| 8.39 |14.90 | 18 3| |Fort Miller | 7.25| 0.00|2.94| 8.81 |19.00 | 6 9| |Fort Point | 3.66| 0.03|2.28|11.39 |17.36 | 14 11| |Monterey | 4.43| 0.26|2.24| 8.78 |15.71 | 12 3| |Sacramento | 5.55| 0.09|2.76|10.84 |19.24 | 18 3| |San Francisco; Presidio | 4.80| 0.49|2.68|12.32 |20.29 | 20 2| |San Francisco | 5.03| 0.22|3.05|13.19 |21.49 | 24 4| +----------------------------+-----+-----+----+------+------+-------+

TABLE IV.--_Precipitation of the Region of the Lower Columbia._

+---------------------------------------------------+ | |Latitude. | | | |Longitude. | | | | |Height.| | Station. | | | | | | | | | +----------------------------+------+-------+-------+ | | ° ´ | ° ´ | Feet. | |Astoria, Oreg |46 11 |123 48 | 52 | |Cape Disappointment, Wash |46 17 |124 03 | 30 | |Fort Dalles, Oreg |45 33 |120 50 | 350 | |Camp Gaston, Cal |41 01 |123 34 | -- | |Camp Wright, Cal |39 48 |123 17 | -- | |Fort Crook, Cal |41 07 |121 29 | 3,390 | |Fort Hoskins, Oreg |45 06 |123 26 | -- | |Fort Humboldt, Cal |40 45 |124 10 | 50 | |Fort Jones, Cal |41 36 |122 52 | 2,570 | |Fort Steilacoom, Wash |47 11 |122 34 | 300 | |Fort Stevens, Oreg |46 12 |123 57 | -- | |Fort Umpqua, Oreg |43 42 |124 10 | 8 | |Fort Vancouver, Wash |45 40 |122 30 | 50 | |Fort Yamhill, Oreg |45 21 |123 15 | -- | |Portland, Oreg |45 30 |122 36 | 45 | |Port Townsend, Wash |48 07 |122 45 | 8 | |San Juan Island, Wash |48 28 |123 01 | 150 | +----------------------------+------+-------+-------+

+----------------------------+-------------------------------+-------+ | | Mean precipitation, | | | | in inches. | | | +-------------------------------+ | | |Spring. | | | | |Summer. |Extent | | | | |Autumn. | of | | Station. | | | |Winter. |record.| | | | | | |Year. | | +----------------------------+-----+-----+-----+------+------+-------+ | | | | | | | Y. M.| |Astoria, Oreg |18.90| 5.72|18.19| 34.80| 77.61| 22 4| |Cape Disappointment, Wash |14.97| 5.97|20.46| 29.84| 71.24| 5 9| |Fort Dalles, Oreg | 3.91| 1.16| 5.78| 11.27| 22.12| 12 8| |Camp Gaston, Cal |14.76| 1.15| 9.92| 31.56| 57.39| 12 0| |Camp Wright, Cal | 8.26| 0.27| 8.17| 27.27| 43.97| 9 8| |Fort Crook, Cal | 6.37| 0.97| 4.55| 11.29| 23.18| 9 0| |Fort Hoskins, Oreg |14.69| 2.65|14.88| 34.48| 66.70| 6 9| |Fort Humboldt, Cal | 9.36| 0.73| 6.49| 18.73| 35.31| 11 2| |Fort Jones, Cal | 5.23| 0.91| 4.19| 11.37| 21.70| 5 0| |Fort Steilacoom, Wash | 8.98| 2.81|10.12| 17.01| 38.92| 12 9| |Fort Stevens, Oreg |17.67| 7.88|18.21| 34.81| 78.57| 6 5| |Fort Umpqua, Oreg |16.83| 2.86|15.64| 32.08| 67.41| 5 10| |Fort Vancouver, Wash | 8.70| 3.78| 9.17| 16.72| 38.37| 16 11| |Fort Yamhill, Oreg |13.10| 2.39|13.20| 26.90| 55.59| 9 3| |Portland, Oreg |13.75| 2.50|11.31| 19.64| 47.20| 7 0| |Port Townsend, Wash | 5.45| 4.22| 2.31| 4.07| 16.05| 5 6| |San Juan Island, Wash | 5.01| 4.60| 7.89| 10.84| 28.34| 9 4| +----------------------------+-----+-----+ ----+------+------+-------+

DISTRIBUTION OF RAIN THROUGH THE YEAR.

In a general way the limit of agriculture without irrigation, or “dry farming”, is indicated by the curve of 20 inches rainfall, and where the rainfall is equally distributed through the year this limitation is without exception. But in certain districts the rainfall is concentrated in certain months so as to produce a “rainy season”, and wherever the temperature of the rainy season is adapted to the raising of crops it is found that “dry farming” can be carried on with less than 20 inches of annual rain. There are two such districts upon the borders of the Arid Region, and within its limits there may be a third.

_First District._--Along the eastern border of the Arid Region a contrast has been observed between the results obtained at the north and at the south. In Texas 20 inches of rain are not sufficient for agriculture, while in Dakota and Minnesota a less amount is sufficient. The explanation is clearly developed by a comparison of the tables of rainfall with reference to the distribution of rain in different seasons.

TABLE V.--_Precipitation of Texas._

+---------------------------------------------------+ | |Latitude. | | | |Longitude. | | | | |Height.| | Station. | | | | | | | | | +----------------------------+------+-------+-------+ | | ° ´ | ° ´ | Feet. | |Austin |30 17 | 97 44 | 650 | |Camp Verde |30 00 | 99 10 | 1,400 | |Fort Belknap |33 08 | 98 46 | 1,600 | |Fort Bliss (El Paso) |31 47 |106 30 | 3,830 | |Fort Brown |25 50 | 97 37 | 50 | |Fort Chadbourne |31 58 |100 15 | 2,020 | |Fort Clark |29 17 |100 25 | 1,000 | |Fort Davis |30 40 |104 07 | 4,700 | |Fort Duncan |28 39 |100 30 | 1,460 | |Fort Griffin |32 54 | 99 14 | -- | |Fort Inge |29 10 | 99 50 | 845 | |Fort Mason |30 40 | 99 15 | 1,200 | |Fort McIntosh |27 35 | 99 48 | 806 | |Fort McKavett |30 48 |100 08 | 2,060 | |Fort Stockton |30 20 |102 30 | 4,950 | |Galveston |29 18 | 94 47 | 30 | |Gilmer (near) |32 40 | 94 59 | 950 | |New Braunfels |29 42 | 98 15 | 720 | |Ringgold Barracks |26 33 | 99 00 | 521 | |San Antonio |29 25 | 98 25 | 600 | +---------------------------------------------------+

+----------------------------+-------------------------------+-------+ | | Mean precipitation, | | | | in inches. | | | +-------------------------------+ | | |Spring. | | | | |Summer. |Extent | | | | |Autumn. | of | | Station. | | | |Winter. |record.| | | | | | |Year. | | +----------------------------+-----+-----+-----+------+------+-------+ | | | | | | | Y. M.| |Austin | 8.61| 7.94|10.74| 6.23| 33.52| 18 8| |Camp Verde | 6.11| 9.81| 8.30| 5.05| 29.27| 5 9| |Fort Belknap | 6.41| 9.44| 8.34| 3.86| 28.05| 5 10| |Fort Bliss (El Paso) | 0.43| 3.49| 3.38| 1.23| 8.53| 14 3| |Fort Brown | 3.18| 7.64|13.02| 4.04| 27.88| 15 0| |Fort Chadbourne | 5.77| 6.53| 7.06| 3.52| 22.88| 8 7| |Fort Clark | 4.14| 7.57| 6.55| 4.35| 22.61| 12 5| |Fort Davis | 1.84| 8.76| 4.72| 1.80| 17.12| 8 11| |Fort Duncan | 3.56| 8.60| 6.54| 2.63| 21.33| 11 7| |Fort Griffin | 4.95| 6.25| 6.14| 4.17| 21.51| 5 3| |Fort Inge | 5.38| 9.67| 6.88| 3.53| 25.46| 7 4| |Fort Mason | 6.36|10.44| 8.22| 3.96| 28.98| 5 1| |Fort McIntosh | 3.22| 6.56| 5.38| 2.35| 17.51| 14 7| |Fort McKavett | 5.21| 6.71| 7.81| 4.22| 23.95| 9 7| |Fort Stockton | 1.24| 5.66| 3.31| 1.29| 11.50| 5 8| |Galveston |13.15|14.90|16.83| 12.19| 57.07| 6 1| |Gilmer (near) |13.36| 9.93|11.77| 10.93| 45.99| 7 9| |New Braunfels | 7.60| 6.90| 8.83| 4.25| 27.58| 5 1| |Ringgold Barracks | 3.71| 7.00| 6.31| 2.58| 19.60| 14 2| |San Antonio | 6.77| 8.91| 9.30| 6.32| 31.30| 10 2| | +-----+-----+-----+------+------+-------+ | Means | 4.62| 6.78| 6.64| 3.69| 21.73| -- --| +----------------------------+-----+-----+ ----+------+------+-------+

TABLE VI.--_Precipitation of Dakota._

+---------------------------------------------------+ | |Latitude. | | | |Longitude. | | | | |Height.| | Station. | | | | | | | | | +----------------------------+------+-------+-------+ | | ° ´ | ° ´ | Feet. | | Fort Abercrombie |46 27 | 96 21 | -- | | Fort Buford |48 01 |103 58 | 1,900 | | Fort Randall |43 01 | 98 37 | 1,245 | | Fort Rice |46 32 |100 33 | -- | | Fort Stevenson |47 36 |101 10 | -- | | Fort Sully |44 50 |100 35 | 1,672 | | Fort Totten |47 56 | 99 16 | 1,480 | | Fort Wadsworth |45 43 | 97 10 | 1,650 | | Pembina |48 57 | 97 03 | 768 | +---------------------------------------------------+

+----------------------------+-------------------------------+-------+ | | Mean precipitation, | | | | in inches. | | | +-------------------------------+ | | |Spring. | | | | |Summer. |Extent | | | | |Autumn. | of | | Station. | | | |Winter. |record.| | | | | | |Year. | | +----------------------------+-----+-----+-----+------+------+-------+ | | | | | | | Y. M.| | Fort Abercrombie | 4.80| 8.67| 3.46| 1.85 |18.78 | 13 6 | | Fort Buford | 3.76| 4.06| 2.01| 2.01 |11.84 | 7 10 | | Fort Randall | 4.72| 6.22| 3.40| 1.18 |15.52 | 15 6 | | Fort Rice | 3.63| 4.87| 1.54| 1.35 |11.39 | 6 1 | | Fort Stevenson | 3.41| 4.97| 2.15| 1.31 |11.84 | 6 2 | | Fort Sully | 6.52| 7.18| 1.70| 1.14 |16.54 | 7 8 | | Fort Totten | 5.18| 7.17| 2.50| 1.59 |16.44 | 5 5 | | Fort Wadsworth | 7.00|10.25| 3.98| 2.92 |24.15 | 6 5 | | Pembina | 4.02| 7.24| 2.71| 1.53 |15.50 | 4 8 | | +-----+-----+-----+------+------+-------+ | Means | 4.78| 6.74| 2.61| 1.65 | 15.78| -- | +----------------------------+-----+-----+-----+------+------+-------+

Table V includes every station in Texas that has a record of five years or more, in all twenty stations. If the means of rainfall for the state be compared with the means for single stations, it will be seen that there is a general correspondence in the ratios pertaining to the different seasons, so that the former can fairly be considered to represent for the state the distribution through the year. Table VI presents the data for Dakota in the same way, and the correspondence between the general mean and the station mean is here exceedingly close. At each of the nine stations, the greatest rainfall is recorded in summer, the next greatest in spring, and the least in winter. Placing the two series of results in the form of percentages, they show a decided contrast:

+-------------+---------+---------+---------+---------+-------+
| | Spring. | Summer. | Autumn. | Winter. | Year. |
+-------------+---------+---------+---------+---------+-------+
| Dakota | 30 | 43 | 17 | 10 | 100 |
| Texas | 21 | 31 | 31 | 17 | 100 |
+-------------+---------+---------+---------+---------+-------+

In Dakota a rainy season is well marked, and 73 per cent. of the rain falls in spring and summer, or at the time when it is most needed by the farmer. In Texas only 52 per cent. of the rain falls in the season of agriculture. The availability of rain in the two regions is therefore in the ratio of 73 to 52, and for agricultural purposes 20 inches of rainfall in Texas is equivalent to about 15 inches in Dakota.

For the further exhibition of the subject, Table VII has been prepared, comprising stations in the Region of the Plains all the way from our northern to our southern boundary. By way of restricting attention to the practical problem of the limit of “dry farming”, only those stations are admitted which exhibit a mean annual rainfall of more than 15 and less than 25 inches. The order of arrangement is by latitudes, and in the columns at the right the seasonal rainfalls are expressed in percentages of the yearly. The column at the extreme right gives the sum of the spring and summer quotas, and is taken to express the availability of the rainfall.

TABLE VII.--_Seasonal precipitation in the Region of the Plains._

+---------------------------------------------------+ | |Latitude. | Mean | | | |Extent |yearly | | Station. | | of | rain- | | | |Record.| fall. | +----------------------------+------+-------+-------+ | | ° ´ | Y. M. |Inches.| |Pembina, Dak. |48 57 | 4 8 | 15.50 | |Fort Totten, Dak. |47 56 | 5 5 | 16.44 | |Fort Abercrombie, Dak. |46 27 |13 6 | 18.78 | |Fort Wadsworth, Dak. |45 43 | 6 5 | 24.15 | |Fort Sully, Dak. |44 50 | 7 8 | 16.54 | |Sibley, Minn. |44 30 | 7 11 | 24.74 | |Fort Randall, Dak. |43 01 |15 6 | 15.52 | |Fort McPherson, Nebr. |41 00 | 6 9 | 18.96 | +----------------------------+------+-------+-------+ |Fort Riley, Kans. |39 03 |20 10 | 24.52 | |Fort Hays, Kans. |38 59 | 6 11 | 22.70 | |Fort Larned, Kans. |38 10 |10 9 | 21.42 | +----------------------------+------+-------+-------+ |Fort Griffin, Tex. |32 54 | 5 3 | 21.51 | |Fort Chadbourne, Tex. |31 58 | 8 7 | 22.88 | |Fort McKavett, Tex. |30 48 | 9 7 | 23.95 | |Fort Davis, Tex. |30 40 | 8 11 | 17.12 | |Fort Clark, Tex. |29 17 |12 5 | 22.61 | |Fort Duncan, Tex. |28 39 |11 7 | 21.33 | |Fort McIntosh, Tex. |27 35 |14 7 | 17.51 | |Ringgold Barracks, Tex. |26 23 |14 2 | 19.60 | +----------------------------+------+-------+-------+

+----------------------------+---------------------------------+ | | Percentage of annual rainfall. | | +---------------------------------+ | |Spring. | | | | |Summer. |Spring | | Station. | | |Autumn. | and | | | | | |Winter.|summer.| +----------------------------+-----+-----+-----+-------+-------+ | | | | | | | |Pembina, Dak. | 26 | 47 | 17 | 10 | 73 | |Fort Totten, Dak. | 31 | 44 | 15 | 10 | 75 | |Fort Abercrombie, Dak. | 26 | 46 | 18 | 10 | 72 | |Fort Wadsworth, Dak. | 29 | 42 | 17 | 12 | 71 | |Fort Sully, Dak. | 39 | 44 | 10 | 7 | 83 | |Sibley, Minn. | 21 | 40 | 29 | 10 | 61 | |Fort Randall, Dak. | 30 | 40 | 22 | 8 | 70 | |Fort McPherson, Nebr. | 36 | 40 | 17 | 7 | 76 | +----------------------------+-----+-----+-----+-------+-------+ |Fort Riley, Kans. | 22 | 43 | 24 | 11 | 65 | |Fort Hays, Kans. | 31 | 27 | 25 | 17 | 58 | |Fort Larned, Kans. | 24 | 45 | 23 | 8 | 69 | +----------------------------+-----+-----+-----+-------+-------+ |Fort Griffin, Tex. | 23 | 29 | 29 | 19 | 52 | |Fort Chadbourne, Tex. | 25 | 29 | 31 | 15 | 54 | |Fort McKavett, Tex. | 22 | 28 | 32 | 18 | 50 | |Fort Davis, Tex. | 11 | 51 | 28 | 10 | 62 | |Fort Clark, Tex. | 18 | 34 | 29 | 19 | 52 | |Fort Duncan, Tex. | 17 | 40 | 31 | 12 | 57 | |Fort McIntosh, Tex. | 18 | 38 | 31 | 13 | 56 | |Ringgold Barracks, Tex. | 19 | 36 | 32 | 13 | 55 | +----------------------------+-----+-----+-----+-------+-------+

The graduation of the ratios from north to south is apparent to inspection, but is somewhat irregular. The irregularity, however, is not greater than should be anticipated from the shortness of the terms of observation at the several stations, and it disappears when the stations are combined in natural groups. Dividing the whole series into three groups, as indicated by the cross lines in Table VII, and computing weighted means of the seasonal ratios, we have--

TABLE VII (_a_).[2]

[2] In computing the several means of Table VII (_a_) from the seasonal means of Table VII, the latter were weighted according to the lengths of the records by which they had been obtained.

+------------------+--------+-------+---------------------------------+ | | | | Percentage of annual rainfall. | | | | +---------------------------------+ | | Mean |Total |Spring. | | | Groups of |latitude|years | |Summer. |Spring | | stations. | of | of | | |Autumn. | and | | | group. |record.| | | |Winter.|summer.| +------------------+--------+-------+-----+-----+-----+-------+-------+ | | ° ´ | | | | | | | |Eight stations in | | | | | | | | |Dakota, Minnesota,| | | | | | | | | and Nebraska | 45 20 | 67 | 29 | 43 | 19 | 9 | 72 | |Three stations | | | | | | | | | in Kansas | 38 45 | 38 | 24 | 41 | 24 | 11 | 65 | |Eight stations | | | | | | | | | in Texas | 29 45 | 85 | 19 | 36 | 31 | 14 | 55 | +------------------+--------+-------+-----+-----+-----+-------+-------+

A moment’s inspection will show that the middle group is intermediate between the northern and southern in all its characters. The spring quota of rainfall progressively diminishes from north to south, and so does the summer, while the fall and winter quotas increase. What is lost in summer is gained in winter, and thereby the inequality of rainfall from season to season is diminished, so that a rainy season is not so well defined in Texas as in Dakota. What is lost in spring is gained in autumn, and thereby the place of the rainy season in the year is shifted. In Dakota the maximum of rain is earlier than in Texas, and corresponds more nearly with the maximum of temperature.

TABLE VIII.--_Seasonal precipitation in the San Francisco Region._

+-----------------+-------+-------+---------------------------------+ | | | | Percentage of annual rainfall. | | | | +---------------------------------+ | |Extent | Mean |Spring. | | | Station. | of |annual | |Summer. |Winter | | |record.| rain- | | |Autumn. | and | | | | fall. | | | |Winter.|spring.| +-----------------+-------+-------+-----+-----+-----+-------+-------+ | | Y. M. |Inches.| | | | | | |Alcatraz Island | 9 5 | 16.49 | 16 | 0 | 11 | 73 | 89 | |Angel Island | 5 11 | 18.58 | 19 | 0 | 15 | 66 | 85 | |Benicia Barracks | 18 3 | 14.90 | 28 | 1 | 15 | 56 | 84 | |Fort Miller | 6 9 | 19.00 | 38 | 0 | 16 | 46 | 84 | |Fort Point | 14 11 | 17.36 | 21 | 0 | 13 | 66 | 87 | |Monterey | 12 3 | 15.71 | 28 | 2 | 14 | 56 | 84 | |Sacramento | 18 3 | 19.24 | 29 | 1 | 14 | 56 | 85 | |San Francisco; | 20 2 | 20.29 | 24 | 2 | 13 | 61 | 85 | | Presidio | 20 2 | 20.29 | 24 | 2 | 13 | 61 | 85 | |San Francisco | 24 4 | 21.49 | 24 | 1 | 14 | 61 | 85 | | +-------+-------+-----+-----+-----+-------+-------+ | Weighted means | -- | -- | 25 | 1 | 14 | 60 | 85 | +-----------------+-------+-------+-----+-----+-----+-------+-------+ Total extent of record = 130 years. Mean of yearly rainfalls = 15.90.

_Second District._--In the San Francisco Region a rainy season is still more definitely marked, but occurs at a different time of year. It will be seen by Tables III and VIII that no rain falls in summer, while the winter months receive 60 per cent. of the annual precipitation, and the spring 25 per cent. The general yearly rainfall of the district is only about 16 inches, but by this remarkable concentration a period of five months is made to receive 13 inches. The winter temperature of the district is no less remarkable, and supplies the remaining condition essential to agriculture. Frosts are rare, and in the valleys all the precipitation has the form of rain. The nine stations which afford the rainfall records given above show a mean spring temperature of 57° (see Table IX). Thirteen inches of rain coming in a frostless winter and spring have been found sufficient for remunerative agriculture.

TABLE IX.--_Mean temperatures, by seasons, for the San Francisco
Region._

+-----------------+-------+------------------------------------------+ | |Extent | Mean temperatures, in degrees Fahr. | | Station. | of +------------------------------------------+ | |record.| Spring.| Summer.| Autumn.| Winter.| Year.| +-----------------+-------+---------+--------+-------+--------+------+ | | Y. M. | | | | | | |Alcatraz Island | 8 6 | 55 | 57 | 60 | 54 | 57 | |Angel Island | 3 1 | 58 | 63 | 61 | 52 | 58 | |Benicia Barracks | 15 7 | 58 | 67 | 62 | 49 | 59 | |Fort Miller | 7 6 | 64 | 86 | 67 | 49 | 67 | |Fort Point | 10 11 | 55 | 59 | 58 | 52 | 56 | |Monterey | 12 5 | 55 | 60 | 57 | 50 | 55 | |Sacramento | 14 0 | 59 | 71 | 62 | 48 | 60 | |San Francisco; | 19 0 | 54 | 57 | 57 | 50 | 55 | | Presidio | 19 0 | 54 | 57 | 57 | 50 | 55 | |San Francisco | 11 2 | 55 | 58 | 58 | 50 | 55 | | +-------+---------+--------+-------+--------+------+ | Means | -- | 57 | 64 | 60 | 50 | 58 | +-----------------+-------+---------+--------+-------+--------+------+

The same winter maximum of rainfall is characteristic of the whole Pacific coast. The Region of the Lower Columbia, with an average rainfall of 46 inches, receives 47 per cent. of it in winter and 24 per cent. in spring. Southward on the coast, Drum Barracks (near Los Angeles) and San Diego receive more than half their rain in winter, but as the whole amount is only 9 inches agriculture is not benefited. The eastern bases of the Sierra Nevada and Cascade Range exhibit the winter maximum of rainfall, and this feature can be traced eastward in Idaho and Nevada, but in these districts it is accompanied by no amelioration of winter temperature. (See Table X.)

TABLE X.--_Seasonal precipitation and temperatures on the Pacific
coast, etc._

+------------------------+-------+----------------------+-------------+ | | | Percentage of | Mean | | | | rainfall. | temperature.| | | Mean +----------------------+-----+-------+ | |annual |Spring. | | | Station. | rain- | |Summer. |Spring. | | | fall. | | |Autumn. | |Winter.| | | | | | |Winter.| | | +------------------------+-------+----+----+----+-------+-----+-------+ | |Inches.| | | | | | | |San Francisco Region | 15.90 | 25 | 1 | 14 | 60 | 57 | 50 | |Region of Lower Columbia| 46.45 | 24 | 6 | 23 | 47 | 51 | 40 | |Drum Barracks, Cal | 8.74 | 26 | 3 | 4 | 67 | 60 | 56 | |San Diego, Cal | 9.31 | 20 | 4 | 20 | 56 | 60 | 54 | |Camp Independence, Cal | 6.60 | 17 | 5 | 9 | 69 | 57 | 39 | |Fort Bidwell, Cal | 20.23 | 24 | 8 | 15 | 53 | 48 | 32 | |Camp Warner, Oreg | 14.41 | 30 | 8 | 17 | 45 | 42 | 29 | |Camp Harney, Oreg | 8.76 | 26 | 13 | 18 | 43 | 47 | 27 | |Fort Colville, Wash | 14.06 | 26 | 22 | 18 | 34 | 45 | 24 | |Fort Walla Walla, Wash | 19.36 | 24 | 11 | 26 | 39 | 52 | 34 | |Camp McDermitt, Nev | 8.53 | 35 | 9 | 13 | 43 | 46 | 29 | |Camp Halleck, Nev | 10.98 | 33 | 11 | 21 | 35 | 45 | 28 | |Fort Lapwai, Idaho | 14.89 | 28 | 16 | 23 | 33 | 53 | 33 | |Fort Boisé, Idaho | 15.48 | 33 | 8 | 16 | 43 | 52 | 30 | +------------------------+-------+----+----+----+-------+-----+-------+

_Third District._--In Arizona and New Mexico there is a general maximum of rainfall in summer, and a restricted maximum in winter. The principal minimum is in spring. In Table XI the stations are arranged according to longitudes, a disposition well suited to exhibit their relations. In eastern New Mexico the distribution of rainfall has the same character as in adjacent Texas, but with a more decided maximum. Half of the total rainfall is in summer and half of the remainder in autumn. Westward the maximum diminishes slightly, but it appears in every station of the two territories. In western Arizona the winter maximum of the Pacific coast asserts itself, and it can be traced eastward as far as Fort Wingate, New Mexico. Except at Camp Mohave, on the western border of Arizona, it is inferior in amount to the summer maximum.

TABLE XI.--_Seasonal precipitation in Arizona and New Mexico._

+----------------------+--------+-------+---------------------------+ | | | Mean | Percentage of | | | |annual | annual rainfall. | | Station. | Longi- | rain- +---------------------------+ | | tude. | fall. |Spring. | Autumn. | | | | | |Summer. |Winter.| +----------------------+--------+-------+------+------+-----+-------+ | | ° ´ |Inches.| | | | | |Western Texas | -- | -- | 19 | 36 | 31 | 14 | +----------------------+--------+-------+------+------+-----+-------+ |Fort Union, N. Mex | 104 57 | 19.15 | 11 | 62 | 20 | 7 | |Cantonment Burgwin, | | | | | | | | N. Mex | 105 30 | 8.65 | 18 | 34 | 28 | 20 | |Fort Stanton, N. Mex | 105 38 | 20.94 | 14 | 51 | 23 | 12 | |Santa Fé, N. Mex | 106 02 | 14.91 | 14 | 46 | 23 | 17 | |Albuquerque, N. Mex | 106 38 | 8.11 | 10 | 54 | 25 | 11 | |Fort Fillmore, N. Mex | 106 42 | 8.42 | 5 | 50 | 36 | 9 | |Fort Selden, N. Mex | 106 55 | 8.49 | 7 | 57 | 22 | 14 | |Fort Craig, N. Mex | 107 00 | 11.06 | 6 | 53 | 31 | 10 | |Fort McRae, N. Mex | 107 03 | 11.59 | 21 | 53 | 20 | 6 | |Fort Wingate, N. Mex | 107 45 | 17.32 | 11 | 38 | 20 | 31 | |Fort Bayard, N. Mex | 108 30 | 14.32 | 11 | 50 | 16 | 23 | |Fort Defiance, Ariz | 109 10 | 14.21 | 14 | 42 | 26 | 18 | |Camp Bowie, Ariz | 109 30 | 15.26 | 9 | 48 | 13 | 30 | |Camp Grant, Ariz | 110 40 | 15.08 | 14 | 41 | 22 | 23 | |Camp McDowell, Ariz | 111 36 | 11.45 | 10 | 42 | 15 | 33 | |Camp Verde, Ariz | 111 54 | 10.85 | 12 | 43 | 22 | 23 | |Camp Whipple, Ariz | 112 20 | 19.28 | 20 | 42 | 11 | 27 | |Camp Mohave, Ariz | 114 36 | 4.65 | 18 | 27 | 20 | 35 | +----------------------+--------+-------+------+------+-----+-------+ |San Francisco Region | -- | -- | 25 | 1 | 14 | 60 | +----------------------+--------+-------+------+------+-----+-------+

In all this region the daily range of temperature is great, and frosts occur so early in autumn that no use can be made of the autumnal rainfall. The yearly precipitation is very small, and the summer quota rarely exceeds seven or eight inches. Nevertheless the Pueblo Indians have succeeded, in a few localities, and by a unique method, in raising maize without irrigation. The yield is too meagre to tempt the white man to follow their example, and for his use the region is agricultural only where it can be watered artificially.