Station.Latitude.Longitude.Height.Mean precipitation, in inches.Extent of record.
Spring.Summer.Autumn.Winter.Year.
° ´° ´Feet.Y. M.
Austin 30 17 97 44 650 8.61 7.9410.74 6.23 33.52 18 8
Camp Verde 30 00 99 10 1,400 6.11 9.81 8.30 5.05 29.27 5 9
Fort Belknap 33 08 98 46 1,600 6.41 9.44 8.34 3.86 28.05 5 10
Fort Bliss (El Paso) 31 47 106 30 3,830 0.43 3.49 3.38 1.23 8.53 14 3
Fort Brown 25 50 97 37 50 3.18 7.6413.02 4.04 27.88 15 0
Fort Chadbourne 31 58 100 15 2,020 5.77 6.53 7.06 3.52 22.88 8 7
Fort Clark 29 17 100 25 1,000 4.14 7.57 6.55 4.35 22.61 12 5
Fort Davis 30 40 104 07 4,700 1.84 8.76 4.72 1.80 17.12 8 11
Fort Duncan 28 39 100 30 1,460 3.56 8.60 6.54 2.63 21.33 11 7
Fort Griffin 32 54 99 14 — 4.95 6.25 6.14 4.17 21.51 5 3
Fort Inge 29 10 99 50 845 5.38 9.67 6.88 3.53 25.46 7 4
Fort Mason 30 40 99 15 1,200 6.3610.44 8.22 3.96 28.98 5 1
Fort McIntosh 27 35 99 48 806 3.22 6.56 5.38 2.35 17.51 14 7
Fort McKavett 30 48 100 08 2,060 5.21 6.71 7.81 4.22 23.95 9 7
Fort Stockton 30 20 102 30 4,950 1.24 5.66 3.31 1.29 11.50 5 8
Galveston 29 18 94 47 30 13.1514.9016.83 12.19 57.07 6 1
Gilmer (near) 32 40 94 59 950 13.36 9.9311.77 10.93 45.99 7 9
New Braunfels 29 42 98 15 720 7.60 6.90 8.83 4.25 27.58 5 1
Ringgold Barracks 26 33 99 00 521 3.71 7.00 6.31 2.58 19.60 14 2
San Antonio 29 25 98 25 600 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.

Station.Latitude.Longitude.Height.Mean precipitation, in inches.Extent of record.
Spring.Summer.Autumn.Winter.Year.
° ´° ´Feet.Y. M.
Fort Abercrombie 46 27 96 21 — 4.80 8.67 3.46 1.85 18.78 13 6
Fort Buford 48 01 103 58 1,900 3.76 4.06 2.01 2.01 11.84 7 10
Fort Randall 43 01 98 37 1,245 4.72 6.22 3.40 1.18 15.52 15 6
Fort Rice 46 32 100 33 — 3.63 4.87 1.54 1.35 11.39 6 1
Fort Stevenson 47 36 101 10 — 3.41 4.97 2.15 1.31 11.84 6 2
Fort Sully 44 50 100 35 1,672 6.52 7.18 1.70 1.14 16.54 7 8
Fort Totten 47 56 99 16 1,480 5.18 7.17 2.50 1.59 16.44 5 5
Fort Wadsworth 45 43 97 10 1,650 7.0010.25 3.98 2.92 24.15 6 5
Pembina 48 57 97 03 768 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.
Dakota30 431710100
Texas 21313117100

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.

Station.Latitude.Extent of Record.Mean yearly rainfall.Percentage of annual rainfall.
Spring.Summer.Autumn.Winter.Spring and Summer.
° ´Y. M.Inches.
Pembina, Dak. 48 57 4 8 15.50 26 47 17 10 73
Fort Totten, Dak. 47 56 5 5 16.44 31 44 15 10 75
Fort Abercrombie, Dak. 46 2713 6 18.78 26 46 18 10 72
Fort Wadsworth, Dak. 45 43 6 5 24.15 29 42 17 12 71
Fort Sully, Dak. 44 50 7 8 16.54 39 44 10 7 83
Sibley, Minn. 44 30 7 11 24.74 21 40 29 10 61
Fort Randall, Dak. 43 0115 6 15.52 30 40 22 8 70
Fort McPherson, Nebr. 41 00 6 9 18.96 36 40 17 7 76
Fort Riley, Kans. 39 0320 10 24.52 22 43 24 11 65
Fort Hays, Kans. 38 59 6 11 22.70 31 27 25 17 58
Fort Larned, Kans. 38 1010 9 21.42 24 45 23 8 69
Fort Griffin, Tex. 32 54 5 3 21.51 23 29 29 19 52
Fort Chadbourne, Tex. 31 58 8 7 22.88 25 29 31 15 54
Fort McKavett, Tex. 30 48 9 7 23.95 22 28 32 18 50
Fort Davis, Tex. 30 40 8 11 17.12 11 51 28 10 62
Fort Clark, Tex. 29 1712 5 22.61 18 34 29 19 52
Fort Duncan, Tex. 28 3911 7 21.33 17 40 31 12 57
Fort McIntosh, Tex. 27 3514 7 17.51 18 38 31 13 56
Ringgold Barracks, Tex. 26 2314 2 19.60 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—