VALLEY, FOOT-HILL AND MOUNTAIN CLIMATE 



VALLEY CLIMATE 



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The characteristics of the interior valley climate are higher 

 summer and lower winter temperatures than on the coast, the 

 range of temperature being nearly the same both north and south ; 

 rainfall abundant in the north and decreasing rapidly southward, 

 so that as a rule the interior valleys in the south half of the State 

 require irrigation; very dry air and almost constant sunshine, 

 freedom from fogs and from dew in summertime; winds occasion- 

 ally strong, hot, and desiccating in summer and cold in winter. 



Local Modifications. The term "valley climate" is broad, and 

 includes everything, away from the coast to a certain elevation 

 on the slope of the mountains. Certain small valleys protected 

 from cold northerly winds and from fog-bearing westerly winds 

 and open to the spring sunshine, have a forcing climate which 

 produces the earliest maturing fruit of the season ; earlier not 

 only than the coast and the mountain, as has been stated, but also 

 somewhat earlier than adjacent locations in the broad, open 

 valley. Slight elevation, even on the sides of small valleys, 

 frequently secures freedom from winter frosts and ministers to 

 early ripening. Elevation above sea-level on the rims- of great 

 valleys also secures similar results and gives rise to thermal belts 

 in which semi-tropical fruits are successfully growing even as far 

 north as Shasta County. On the floors of great valleys moderating 

 influences are secured on the lee side of wide rivers and by 

 planting on the river bank or on slightly elevated swells rather 

 than on the level, open plain. The river bottom lands of the great 

 valleys, though subject to severe frosts, are freer from the effects 

 of desiccating winds than the open plains ; they are, however, 

 more favorable to the spread of certain blights than the plains. 



Some of the horticultural effects of valley conditions are as 

 follows: Early ripening and perfection of summer and autumn 

 fruits, owing to continual sunshine and dry air; forced maturity 

 of certain fruits, as apples for instance, which destroys character 

 and keeping quality; injury from sunburn and hot winds in 1 

 summer, which seriously affect both fruit and foliage of some 

 varieties; occasional injury to tender fruits (semi-tropicals) 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, counterbalanced 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 summer fog, dew, 

 and generally from rain during the drying season. 



