Arizona Agricultural Experiment Static 



N 



313 



Table XXVIII— Continued. 



■'Not given, ffiescott data 1909 to 1912 inc. 



The terms "killing frost" and '"freezing temperature" as far as dam- 

 age to vegetation is concerned, are not strictly interchangeable. How- 

 ever, in an arid section, a killing frost seldom occurs until the tempera- 

 ture of the air has fallen somewhat below freezing point ; and, moreover, 

 the range in daily temperature being relatively great, the duration of 

 freezing temperatures is shorter. Thus frost temperatures may often 

 be experienced with little harm to vegetation. The growing sea.son in 

 the northern part of the State at the higher altitudes is very short, and 

 hard freezes arc common late in spring and early autumn. Destructive 



