CEREAL EXPERIMENTS AT THE AKRON FIELD STATION. 9 



Table VI. — -Mean, viaximum, and minimum temperatures at the Akron Field Station, 

 Akron, Colo., by months, 1908 to 1915, inclusive, so far as data are available. 



[Data (in ° F.) from the records of the Biophysical Laboratory of the Bureau of Plant Industry.] 



Year. 



1908. 

 1909. 

 1910. 

 1911. 

 1912. 

 1913. 

 1914. 

 1915. 



Average. 



January. 



February. 



37 



March. 



April. 



May. 



69 



June. 



Year. 



1908 

 1909 

 1910 

 1911 

 1912 

 1913 

 1914 

 1915 



July. 



84 



56 



August. 



69 



85 



September. 



46 



October. 



52 



65 



35 



November. 



40 



56 



25 



December. 



Table VII gives the dates of the last spring and the first fall frosts 

 and the number of days in the frost-free period of each year from 1909 

 to 1915, inclusive. The latest date on which frost has occurred in 

 the spring during the seven years was May 20, and the average date is 

 May 13. The earliest frost in the fall was September 13, and the 

 average date is September 26. A temperature low enough to cause 

 some injury occurred on August 25, 1910. 



T.\BLE VII. — Annual and average dates of killing frosts,''- the last in spring and the first 

 in autumn, vnth the annual and average length of the frostfree period, at the Akron 

 Field Station, Akron, Colo., 1909 to 1915, inclusive. 



[Data from the records of the Biophysical Laboratory of the Bureau of Plant Industry.] 



Item. 



1909 



1910 



1911 



1912 



1913 



1914 



1915 



Average. 



Frost: 



Last in spring 



First in fall 



Frost-free period, 

 days 



May 14 

 2 Oct. 9 



148 



May 21 

 Sept. 25 



127 



May 10 

 Oct. 3 



146 



May 14 

 Sept. 20 



129 



May 4 

 Sept. 24 



143 



May 12 

 Sept. 13 



124 



May 20 

 Oct. 4 



137 



May 13 

 Sept. 26 



136 







' A temperature of 32' F. is considered frost in the spring when vegetation is tender and a temperature 

 Ijelow 32'' F. is considered frost in the fall. 

 ' Record from Lcroy, Colo. 



50400°— Bull. 402 —16 2 



