1020 
In the lower valleys the amount of 
sunshine is large, especially during the 
summer months; the greatest cloudiness 
is usually found in spring. 
At the lower levels the wind move- 
ment is light, and is commonly of the 
mountain and valley type. The wind 
blows toward the mountains in the 
afternoon, and in localities attains con- 
siderable velocity. After sunset the 
wind subsides, and toward morning 
there is a light breeze from the moun- 
tains toward the lower levels. At the 
summits of the mountains the winds are 
generally from the west, and are fre- 
quently very strong in winter and 
Spring. 
The precipitation, up to the 10,000- 
foot level, is fairly represented by the 
table. It will be seen that, in the princi- 
pal agricultural districts, the average 
is less than 15 inches, and is less than 
10 inches over important areas. There 
is an increase in precipitation with alti- 
tude up to the highest points where ob- 
servations have been made; an annual 
mean of more than 40 inches is indi- 
cated for certain localities. 
By far the most important part of the 
precipitation occurs in winter and early 
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Rig 6 Grand Junction Fruit District, Show- 
ing Position of District Below the 8,000-foot 
level (U §S Weather Bureau ) 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
spring, March and April being usually 
the months of heaviest snowfall. In the 
southein counties there is a pronounced 
tendency toward drought in late spring 
and early summer; June is often prac- 
tically rainless. From the latter part 
of July until September, thunderstorms 
are common, but the precipitation is sel- 
dom heavy, except in the San Juan 
mountains 
The snowfall in the lower valleys is 
light, and remains on the ground but a 
short time. With increasing elevation, 
the depth increases rapidly; mear the 
mountain summits a total fall of over 
30 feet has been observed in a single 
year At the very highest levels, prac- 
tically all the precipitation is in the 
form of snow. Although the depth of 
snow varies much from year to year, 
the fall 1s so great that there are but 
few streams in this section that do not 
carry enough water for present needs, 
even in a dry season. 
E'REDERICK H. BRANDENBURG, 
District Forecaster. 
The Occurrence of Injurious Spring Tem- 
peratures in the Fruit Districts of 
Western Colorado 
The fruit district under consideration 
embraces portions of the Grand and 
Gunnison valleys and branches thereof 
in Mesa, Delta, Montrose and Garfield 
counties in Western Colorado. The fruits 
principally raised are apples, peaches 
and pears. On account of variations in 
elevation, topography, air drainage, etc, 
fruit in some sections reaches a tender 
stage and is liable to injury (sometimes 
by the latter part of March), while that 
in other sections is still dormant. But, 
on the other hand, the later localities are 
the most likely to be visited by late 
Spring freezes, and danger there is not 
entirely over until after the first of June. 
The Grand valley fruit section is the 
lowest in elevation in the district and, 
in general, the earliest. Near the upper 
end it is narrow, and protected on the 
north by the Little Book cliffs, which 
rise more than a thousand feet abruptly 
almost from the edge of the orchards. 
In general the valley slopes towards the 
