CEREAL INVESTIGATIONS ON THE BELLE FOURCHE FARM. 3 
about 60 miles north and 30 miles west of Newell. Aberdeen is 
directly east of Camp Crook, but is about 90 miles from the eastern 
boundary. Pierre is on the Missouri River in the central portion of 
the State. Brookings is in the same latitude as Pierre, but within 20 
miles of the eastern boundary. 
TasLe VII.— Mean monthly and annual temperatures at Newell, Camp Crook, Aberdeen, 
Pierre, and Brookings, S. Dak., for the periods indicated. 
[Data (in °F.) for Newell from the records of the Biophysical Laboratory of the Bureau of Plant Industry 
and for other stations from the records of the United States Weather Bureau. ] 
Newell. cau, Aberdeen. Pierre. Brookings. 
Months. 
6 years 20 years 23 years 21 years 24 years 
(1908-1913).| (1894-1913).} (1891-1913).| (1893-1913). (1890-1913). 
UCN RI Nice agaeneanesace se rEneon sorb eraree 215.0 Wt 9.6 14.1 1G. 
TIGR sack sonacasSoconccomecosgacs ceases a 19.0 18.9 Lith? 16.9 382 
IMIar CHM cee einem eens es oes Sale aeersiols, 2 a 31.8 28. 2 26. 2 29. 4 28.5 
Ail cease aban seoces Seep eaans asec nop esas 45.8 43.9 44.8 46. 7 45.0 
A ET oso se Bree EE aes le es G8e 1) 54.1 55.9 59. 1 55; 2 
a UM Cae ea ee Se ee oe ea Ske 67.0 63. 2 66. 1 69. 1 65. 1 
i UMlyseeen mom ee aeons cree scl etek ez 69.5 70.9 15. 2 69. 6 
NOBUS ba cs dct scacsasces cevesee se oseEcossaae 69. 7 68. 7 68. 7 73.3 67.9 
SOD NE one dogceccoseuesessceacesceucoe 59. 0 58. 6 59. 0 62.9 59. 7 
@Octobers-==--—-: CS Be = ee Se aa ee eee 45.3 45.6 45.7 48.9 46.3 
INOVeIMmbeEResss at ties eee see Cee eee BB h 74 Sleds 28. 8 32.0 29.5 
eae) CCCI CI et ean oe as eee eis 21.3 23. 7 16.9 20.5 19.6 
ANTSGLTE EP Sec Sie Re 44.4 43.6 42.0 45.7 42.7 
a For five years only. 
The record of mean temperatures at Newell is for a much shorter 
period than the records for the other localities noted in Table VII, 
so that the figures are not entirely comparable. The annual mean 
and monthly mean temperatures at Newell differ only slightly from 
_ those at Camp Crook. 
The annual mean temperatures in western South Dakota are shown 
to be shghtly higher than those in the eastern part of the State. The 
difference between the mean temperature at Camp Crook and at 
Aberdeen is 1.6 degrees, while that of Pierre is 3 degrees higher than 
that of Brookings. The variation between the Brookings and Pierre 
temperatures is quite constant throughout the year, but most of the 
variation between the Camp Crook and Aberdeen temperatures oc- 
curs in December, January, and February. The average of the 
mean temperatures for these three months is 7.9 degrees lower at 
Aberdeen. This variation in winter temperatures perhaps accounts 
for the fact that winter wheat is more likely to winterkill in eastern 
than in western South Dakota. 
Table VIII gives the dates of the last spring and first fall frosts 
and the number of days in the frost-free period during each year from 
1908 to 1913, inclusive. The latest date on which frost has occurred 
in the spring during the six years was May 23, and the average date 
