4 Bulletin 77 



A study of the data shows the mean temperature to range 

 from 59.0° at Willcox to 75.4° at Mohawk, the lowest temperature 

 to range from 0° F. to 22° F.; the highest temperature to range 

 from 101° F. to 127° F., with a general average of approximately- 

 Ill" F.; the earliest date of killing frost in autumn to vary from 

 October 6 at Thatcher to December 5 at Mohawk; general killing 

 frosts rarely if ever occur except in the valley lands; the latest frost 

 in spring varies from February 14 at Mohawk to May 27 at Will- 

 cox; and the length of the growing season varies at each station 

 with wide ranges in duration of growing season at the same stations 

 in different years. 



Considering temperature as a limiting factor, the data in Table I 

 show the Lower Colorado Valley and mesa country and the Salt 

 River Valley to be quite free from dangerous temperatures; and for 

 most years the growing seasons, measured in the number of days 

 from the last killing frost in spring to the first killing frost in 

 autumn, are phenomenally long. Within these areas are many 

 thousands of acres of land well adapted to fig culture, being not 

 only frostless but nearly rainless. Throughout these areas the 

 Smyrna fig, when caprified, should produce satisfactory returns in 

 most seasons. Throughout the higher elevations where the climate 

 is more severe, with the possible exception of a few small isolated 

 areas, the Adriatic type is the more desirable form. 



Precipitation. — ^Precipitation occurs principally during two por- 

 tions of the year, a summer maximum during July to vSeptember 

 and a secondary maximum during the colder portion of the year. 

 During April, May, and June the area is practically rainless and but 

 little occurs during the late autumn months. In the eastern half 

 of the State the rainfall varies from 10 to 25 inches per year, while 

 in the western section precipitation varies from 1 to 10 inches. 

 Rainfall increases with the elevation. The character of the pre- 

 cipitation, the time of occurrence, the distribution during the 

 several periods of the year, the amount each month, and the varying 

 periods of heavy and light precipitation are questions of vital im- 

 portance in the production of the fig. The following data compiled 

 from various sources show the character of the precipitation occur- 

 ring at several places in the State where the fig is being grown. 



