4 BULLETIN 297, U. S. DEPARTMENT OF AGRICULTURE. 
PRECIPITATION. | 
The climate of western South Dakota is fairly typical of that of 
the semiarid Great Plains, which extend from western Texas into 
the prairie provinces of western Canada. The precipitation decreases 
steadily from the eastern border of the State to the western, being 
least in the north- 
AAINFALL IN INCHES . WHOS OCENSE. 
————— 2 The Black Hills 
seem SSS modify the climate 
EE WI F ae ae 
I ON | of the immediately 
— WSS surrounding country 
Foes eater  WXX gg gagasy tO, fa Seats sexemir 
EI WO mainly by increasing 
a  CRCO?CG the precipitation. 
A , ee This effect extends 
Fig. 1.—Diagram showing the annual and seasonal precipitation at 
the Belle Fourche Experiment Farm, for six years, 1908 to 1913, in- several miles beyond 
_clusive. Solid bars show the seasonal precipitation, while the total the outlying foothills. 
length of the bars shows the annual precipitation. 
The Belle Fourche 
farm is situated about 30 miles from the foothills and, so far as known, 
is not influenced to any extent by proximity to the Black Mills. The 
annual and average precipitation by months at the Belle Fourche Ex- 
periment Farm for the six years from 1908 to 1913 is given in Table 
II. Except as noted, these data were recorded at thestation. The 
annual and seasonal rainfall is shown graphically in figure 1. 
TasLe I].— Monthly, seasonal, and annual precipitation at the Belle Fourche Experiment 
Farm for the siz years from 1908 to 1913, inclusive. 
[Data (in inches) from the records of the Biophysical Laboratory of the Bureau of Plant Industry, except 
as noted.] 
= Sea- | To- 
Year. Jan. | Feb. | Mar. | Apr. | May.| June.|July.| Aug. |Sept.| Oct. | Nov. | Dec. SOnnIG ara 
1908......-.---|@0.20 a0. 19 |a1.65 | 1.16 | 3.95 | 1.47 | 1.26 | 0.62 | 0.52 |a2.10 |a0. 20 |a0.91 | 9.49 | 14. 23 
T1QOQIe er cee Qi \ a. 23 | a 19 | 284° 3.87 | 5. 59) 2545 S554 |e O71 a6 |= evisnlels 26n ba O 4m etientcs 
ONO Re Sea aoen 73a AON) 3938) MeO Vale 26h | eeole 4 Dn IOS SON O2 ae ales eel Obl as Om wel carers 
GH eer Me aa 513°) 205) S095) SLs 4 onl 508! 80) | Sle S64 2925 soon OSa| leer O neon Oler peGaGe 
IGN Pe See ee 224 \ SION |e 722325825265) = 229563520) 25 80k oa On ea ode 045 Seas ee iene Os0o, 
LON GMa 2 OW | 24 1 997) S25) 98 | Sol OS So 26n 2e38ulp de sO seed Ol ee tion |p OmGialmtecs 
Average...) .37 | ~26 | 2765/2055) 25:29) | 22085 oS aleie1O a GE SShie Or esSON meso on mieraom il oer 
Maximum] .73]| .70 | 1.65 | 2.32 | 3.95 | 5.59 | 3.20 | 2.80 | 3.49 | 2.10 | .98 | 1.28 |12.94 | 17.73 
Minimums) 139) 305) 090 eda S45 se S298 Sonar 26 5 | lest 2a lela 7 ome eon ered Oe Oe ee en 
a From records of the United States Weather Bureau at Vale and at Orman, S. Dak. 
The average precipitation at the Belle Fourche Experiment Farm 
during the 6-year period under discussion (1908-1913), as shown in 
Table II, was 13.41 inches. Of this total, 7.76 inches fell during the 
months from March to July, inclusive, or during the period when 
small grains make most of their growth. The annual precipitation 
varied from 6.64 inches in 1911 to 17.73 inches in 1909. The seasonal 
