BULLETIN 1172, U. S. DEPARTMENT OF AGRICULTURE. 
Precipitation is lighter in the middle of the valley than at the 
margins on either side. On the east side of the Sacramento River 
the precipitation increases from south to north, but on the west side 
it decreases slowly to the northward as far as Williams and then 
increases again toward the north. 
Summer in the Sacramento Valley is marked by a long period of 
high temperatures by day. These, however, are moderated by 
comparatively low night temperatures. The difference between day 
and night temperatures averages about 40° F. The maximum tem- 
perature at Red Bluff in summer in a 33-year period was 114° F., 
while the maximum at Sacramento in summer in a 62-year period 
was 110° F. Sea breezes from San Francisco Bay moderate the 
temperatures in the south. The winters, on the other hand, are 
mild with no low temperatures. At Red Bluff in the period stated 
the minimum was 18° F., and at Sacramento in the 62-year period 
it was 19° F. Usually only thin films of ice form in winter during 
the occasional cold periods. 
In general, the Sacramento Valley is an area of comparatively 
low wind movement. However, at certain seasons of the year 
moderately strong winds frequently occur. The prevailing winds 
are from the south and are strongest in the middle of the valley 
and at its south end. In spring and early summer north winds are 
not infrequent. Strong drying winds of three or more days duration, 
locally known as " northers/' are not uncommon and frequently 
become destructive by reducing the moisture supply in growing 
grain or other crops or by shattering ripened grain. 
In the winter or rainy season the humidity is high and evaporation 
low; during the cloudless days of spring and summer the reverse 
conditions obtain and evaporation is correspondingly high. Evapora- 
tion is greatly increased during a "norther." 
CEREAL PRODUCTION. 
The principal dry-land cereals grown in California are wheat and 
barley. The industry began about 1850 and reached its maximum 
about 1880, when California was one of the leading wheat-producing 
States in the Union. Since that date the more fertile grain landsQ 
have been devoted to fruit growing, and the acreage and production 
of cereals have decreased steadily except for a few years during and 
after the World War, when high prices greatly stimulated wheat 
production. Barley also has largely displaced wheat on the lighter 
lands, so that now it is a more important crop than wheat. 
Table 1. — Comparison of acreage and production of wheat, barley, and oats in the 
Sacramento Valley and in the State of California in the year 1919. 
Area grown. 
Production. 
Crop. 
In the 
valley. 
In the 
State. 
Part of 
total. 
In the 
valley. 
In the 
State. 
Part of . 
total. 
Wheat 
Acres. 
385,816 
339,927 
49,376 
Acres. 
1,086,428 
987,068 
146,889 
Per cent. 
35.5 
34.4 
33.6 
Bushels. 
6,611,868 
8,381,245 
788, 857 
Bushels. 
16,866,882 
21,897,2,83 
2,966,776 
Per cent. 
39.2 
Barley 
Oats 
38.3 
26.6 
