BULLETIN 398^ U. S. DEPARTMENT OP AGRICULTURE. 



Measurements of the wind velocity have been taken since 1910 at 

 the Judith Basin substation by the Biophysical Laboratory of the 

 Bureau of Plant Industry. The records are taken during six months, 

 April to September, inclusive. The anemometer stands near the 

 evaporation tank, at a height of about 2 feet above the surface of 

 the ground. Table VII gives the average wind velocity from April 

 to September in the six years from 1910 to 1915, inclusive. 



Table VII.- — Average wind velocity {in miles per hour) at the Judith Basin substation. 

 Moccasin, Mont., by months, from April to September of each year from 1910 to 1915, 

 inclusive. 



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



Year. 



Apr. 



May. 



June. 



July. 



Aug. 



Sept. 



Average. 



1910 



9.0 

 7.8 

 6.6 

 8.7 

 6.3 

 7.6 



6.8 

 8.0 

 7.6 

 6.5 

 7.5 

 7.5 



6.3 

 5.4 

 5.7 

 5.3 

 6.4 

 6.6 



5.9 

 5.9 

 5.1 

 5.0 

 5.5 

 5.1 



6.0 

 5.9 

 6.4 

 5.4 

 6.0 

 4.9 



4.0 

 5.3 

 6.7 

 6.5 

 7.2 

 5.9 



6.33 



1911 



6.38 



1912 



6.35 



1913 



6.23 



1914 



6.48 



1915 .' 



6.26 









7.7 



7.3 



6.0 



5.4 



5.8 



5.9 



6.35- 







Table VII shows that April has the highest average wind velocity 

 7.7 miles per hour. The average wind velocity decreases through 

 May, June, and July, but increases again slightly in August and Sep- 

 tember. The 6-year average velocity in the six months is 6.35 miles 

 per hour. 



TEMPERATURE. 



Table VIII gives the mean, maximum, and minimum tempera- 

 tures at the Judith Basin substation by months from April to Sep- 

 tember of each year from 1909 to 1915, inclusive. The highest aver- 

 age mean temperatures occur in July and August, 63° F., and the 

 highest average maximum in August, 77° F. Temperatures as high 

 as 95° F. are rare in the Judith Basin. When hot weather occurs it 

 lasts for only a short time. Hot, drying winds are uncommon. In 

 only one year since the station was started have hot winds done any 

 damage to the growing crops. 



Table VIII. — Mean, maximum, and minimum temperatures (°F.) at the Judith Basin 

 substation. Moccasin, Mont., by months, from April to September of each year from 

 1909 to 1915, inclusive. 



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





April. 



May. 



June 





July. 



August. 



September. 



a 



Year, 



:! 



a 

 1 



V. 



03 



a 

 a 



1 



a 

 a 



1 



a 

 1 



S 



a 

 1 



a 



a 

 ■a 



1 



6 



1 

 V. 



a 



1 



•a 



03 

 1 



a 



1 



03 



a 



a 

 •a 

 i 





a 



3 



a 

 1 



a 



1 

 a 



a 



1909 



35 

 49 

 38 

 43 

 43 

 42 

 50 



44 

 65 

 51 

 55 

 55 

 56 

 62 



25 

 34 

 26 

 31 

 31 

 29 

 37 



49 

 51 



48 

 50 

 49 

 51 

 49 



60 

 62 

 59 

 60 

 63 

 65 

 59 



38 

 41 

 37 

 37 

 38 

 37 

 38 



58 

 60 

 60 

 61 

 60 

 57 

 52 



68 

 74 

 71 

 74 

 73 

 69 

 62 



47 

 47 

 47 

 45 

 48 

 45 

 42 



63 



68 

 62 

 61 

 62 



68 

 58 



74 

 82 

 77 

 75 

 76 

 83 

 69 



50 

 53 

 45 

 47 

 48 

 51 

 46 



65 

 62 

 58 

 62 

 65 

 62 

 66 



78 

 75 

 70 

 76 



81 

 77 

 81 



50 



47 

 47 

 47 

 49 

 45 

 51 



59 

 53 

 50 

 48 

 55 

 56 

 49 



68 

 63 

 62 

 60 

 72 

 71 

 59 



49 

 41 

 38 

 35 

 40 

 40 

 38 



55 



1910 



57 



1911 



52 



1912 



54 



1913 



56 



1914 



■56 



1915 



54 







Average 



43 



55 



30 



49 



61 



38 



58 



70 



46 



63 



76 



49 



63 



77 



48 



53 



65 



40 



55 



