16 foot-hill Climate. 
in summer, which seriously aftect both fruit and foliage of some 
varieties; occasional injury to tender fruits (semitropicals) and 
to young trees of hardy fruits, which have been kept growing 
late in the season, from low temperature, which sometimes is 
reached suddenly on the floor of the valleys; freedom from some 
blights and insects which are prevalent on the coast, but not 
from others. Many of these minor troubles are, however, coun- 
terbalanced by the earliness, size, beauty, and quality of certain 
fruits, and by the most rapid and successful open-air drying of 
fruits, owing to high autumn temperature, the freedom from fog, 
dew, and generally from rain during the drying season. 
FOOT-HILL CLIMATE. 
Foot-hill climate is usually considered as a modification of 
valley climate. It has been shown that up to about two thou- 
sand five hundred feet, on the western slope of the Sierra Ne- 
vada, the seasonal temperatures are quite like those of the val- 
ley, but the rainfall increases about one inch for each hundred 
feet of elevation. There are, however, in the foot-hills, places 
where early spring heat and freedom from frost give very early 
ripening fruits, and other places at the same elevation where win- 
ter temperature drops below the valley minimum, and where late 
frosts also prevail. This is governed by local topography. In 
many of the small valleys among the foot-hills, bordering upon 
the great central valley of the State, and in the Coast Range as 
well, frosts are more severe than on the hills adjacent. The por- 
tions of these highland valleys most affected are usually the very 
lowest, the moist lands of the creek bottoms, or the wet swales, 
where there are such. Growths on the black or dark-colored 
soils, which are so situated as to be well drained and warm, are 
hable to frost, while those on the red lands and those of a 
chalky or ashen hue escape. The direct rays of the sun upon 
the darker earth hasten the spring growth beyond that on soil of 
lighter color. Hence if, other causes combining, there comes a 
frost, the earlier vegetation of the dark land suffers more than 
adjoining lands of a different description. These sudden 
changes to either extreme occur on the low grounds of the foot- 
hills to a far greater extent than upon the surrounding hills and 
ridges, or in the broad valleys of the Sacramento and San Joa- 
quin. 
Of course the disposition of cold air to settle in low places 
and to flow down cafions and creek-beds while the warm air 
rises and bathes the adjacent hillsides, has much to do with the 
frost in the hollow and the freedom from it on the hills, irrespect- 
ive of color or character of soil. The constant motion of the 
air on the slopes is also a preventive of frost, providing the gen-. 
