SHEEIDAK" FIELD STATION, 1917 TO 1923 
tures of 100° F. or more occur but seldoni during a season and fre- 
quently not at all. 
Table 1. — Monthly, seasonal, and annual precipitation at the Sheridan Field 
Station for the 7-year period from 1917 to 1923, inclusive, the average for the same 
period from the United States Weather Bureau record at Sheridan, the 31-year 
average for Sheridan, and the 7-year seasonal averages at Verona and Gillette, 
Wyo. 
' 
1 
! 
Sea- 
Station and 
year 
Jan. 
Feb. 
Mar. 
Apr. 
May June 
July 
Aug. 
Sept. 
Oct. 
Nov. 
Dec. 
sonal, 
April 
to Au- 
gust 
An- 
nual 
Sheridan 
Field Sta- 
tion: 
1917 
0.84 
0.37 
1.31 
0.63 
3.84 
1.36 
0.09 
0.43 
0.08 
1.02 
0.08 
0.78 
6.35 
10.83 
1918 
1.56 
.08 
1.65 
2.92 
3. 18 1 1. 54 ; 1. 16 
1.02 
2.60 
.80 
.60 
.15 
9.82 
17.26 
1919 
.26 
.23 
.21 
.94 
1. 01 1 1. 12 ; . 77 
.30 
1.16 
1.80 
.62 
.14 
4.14 
8.56 
1920 
.46 
.38 
.49 
2.35 
2. 68 i 3. 11 1 1. 11 
.56 
.45 
1.13 
.60 
.32 
9.81 
13.64 
1921 
.44 
.02 
.65 
.94 
2. 08 2. 63 1. 41 
.30 
.35 
.21 
1.38 
.20 
7.36 
10.61 
1922 
1.27 
.19 
.35 
2.63 
2. 82 1 3. 48 , 3. 12 
1.27 
.15 
1.26 
.82 
.59 
13.32 
17.95 
1923 
.41 
.22 
1. 34 2. 37 
1. 95 2. 94 1 3. 45 
.85 
9.35 
1.54 
.43 
.33 
11.56 
25.18 
7-year 
i 

aver- 
age- 
.75 
.21 
.86 
1.83 
2.51 
2.31 
1.59 
.68 
2.02 
1.11 
.65 
.36 
8.92 
14.88 
Sheridan 
! 
' 
Weather 
i 
Bureau: 
Aver- 
age, 
■ 
1917 
to 
1923. 
.94 
.37 
1.25 i 2.29 
2. 82 i 1. 57 
1.84 
.85 
1.86 
1.38 
.73 
.64 
9.37 
16.54 
Aver- 
1 
age, 
j 
1893 
1 
1 
to 
1 
1923, 
.89 
.70 
1.19 
1.72 
2. 72 1 1. 92 
1.23 
.76 
1.49 
1.03 
.63 
.62 
8.35 
14.90 
Verona: 
Aver- 
age, 
1917 
to 
1923. 
1.71 
2.63 
1.72 
1.36 
.74 
8.16 
Gillette:! 
Aver- 
age, 
1917 
to 
1923. 
1.79 
1. 84 i 2. 91 
1.72 
2.07 
10.33 
' Record not complete for all months of the seven years. 
The average vdnd velocity is relativel}^ low for the Great Plains. 
Winds causing destructive soil blo^^ng are of rare occurrence. 
The station records of evaporation, temperatures, and wind velocity 
are given in Table 2. The evaporation was recorded in daily microm- 
eter measurements of the change in the water level in a tank 24 inches 
deep and 6 feet in diameter sunk to a depth of 20 inches in the ground. 
The temperatures were recorded in a standard Weather Bureau shel- 
ter. The wind velocity was measured by a Robinson cup anemome- 
ter exposed at a height of 24 inches. 
The average frost-free period for the seven years specified was 
131 days. The earliest killuig frost in the fall was August 29, 1920. 
A large part of the surrounding country w^as not frosted at that 
time. The earliest date of killing frost in the other six years was 
September 11, and in four of the seven years there was no killing 
frost until well into October. Weather during the fall generally is 
quite favorable for taking care of field crops. Frost data recorded 
