10 



BULLETIN 30, U. S. DEPARTMENT OF AGRICULTURE. 



monthly averages for the past four years. Strong winds at Nephi 

 are very infrequent and no exceptionally high velocities have been 

 recorded. The wind for any one day (24 hours) very seldom exceeds 

 a total of 200 miles, while the average velocity does not exceed 10 

 miles an hour. The wind is usually from the south and southwest in 

 the morning, but during the day it gradually changes until by evening 

 it is blowing from the north and northeast. Protracted hot winds are 

 practically unknown. 



TEMPERATURE. 



The maximum and minimum temperatures are determined daily at 

 the substation from April 1 to October 31, inclusive. The work was 

 started June 1, 1908. A maximum and a minimum thermometer, as 

 well as an air thermograph, are in constant use during the summer 

 months. A summary of the mean, maximum, and minimum tem- 

 peratures during April to October, inclusive, for the past four years 

 is presented in Table V. 



Table V. — Summary of mean, maximum, and minimum temperatures (° F.) at the 

 Nephi substation by months from April to October for the years 1909 to 1912. 



Month. 



1910 



1911 



1912 



Average. 



Him 



Average. 



Minimum. 



Average. 



April 



May 



June 



July 



August 



September 

 October. . . 



Table V shows that the highest average mean and maximum 

 temperatures have been recorded in July, while the lowest have been 

 recorded for April and October. Only three of the months, June to 

 August, inclusive, have been free from frost. Table VI gives the dates 

 of the last spring and first fall frosts and the number of days in the 

 frost-free period during each year from 1908 to 1912, inclusive. 



Table VI. — Killing frosts at the Nephi substation for the years 1908 to 1912, with tempera- 

 tures recorded and length of frostfree period. 



Year. 



1908 



1909 



1910 



1911 



1912 



Average 



Last in spring. 



June 22 



May 30 



May 16 



May 27 



June 16 



June 4 



Minimum 

 tempera- 

 ture. 



F. 



30 



30.5 



28 



28 



31 



29.5 



First in fall. 



Date. 



Aug. 30 

 Sept. 12 

 Oct. 5 

 Sept. 17 

 Sept. 4 



Minimum 

 tempera- 

 ture. 



Sept. 14 



F. 

 31 



30.5 

 29 

 29 

 30 



29.9 



Frost- 

 free 

 period. 



Days 



09 

 105 

 142 

 113 



80 



