8 



FIELD OPERATIONS OF THE BUREAU OF SOILS, 1916. 



storms, sometimes almost cloudbursts, as well as rather long dry 

 spells, may occur during the growing season. The precipitation in 

 the driest year on record (1910) was 11.59 inches, and in the wettest 

 year (1868), 41.64 inches. The average annual snowfall amounts to 

 41.8 inches. Snow often covers the ground for long periods. 



The mean annual temperature is 44.7° F. The mean temperature 

 for the summer is 69.6° F., and for the winter 16.5° F. The lowest 

 temperature on record is — 33° F., reached in both January and 

 February, and the highest temperature recorded is 102° F., in July. 



The average date of the last killing frost in the spring is April 

 28, and that of the first in the fall October 8. The average growing 

 season is thus 163 days in length, and is sufficient for maturing all 

 the comm(m crops. The latest killing frost recorded in the spring 

 occurred on May 20, and the earliest in the fall on September 13. 

 Corn, the crop most subject to injury, is almost invariably matured 

 even in years with abnormnlly short growing seasons. 



Fall and spring winds sometimes do considerable injury on the 

 sandy soils of the county, even after the young growth of grain or 

 other crops is fairly well started. Small fruits such as strawberries, 

 raspberries, and grapes are subject to injury from the alternate 

 freezing and thawing that takes place throughout the winter, un- 

 less protected by a snow cover. A good depth of snow can not be 

 relied upon, and the plants are usually protected by a covering 

 of straw or soil applied in the fall. Exposed grass and clover 

 fields may occasionally be winter-killed. 



The following table, compiled from the records of the Weather 

 Bureau station at Minneapolis, shows in detail certain climatic 

 .data applicable to Anoka County: 



Normal monthly, fteasonal, and annual temperature and precipitation at 

 Minneapolis, Hennepin County. 



