6 



BULLETIN 1244, V. S. DEPARTMENT or AGRICULTURE. 



Table 3 gives the monthly, seasonal, and annual precipitation at 

 Havre, Mont., for 1915 to 1922, inclusive, and the averages for the 

 same period. The averages are also shown for the 43 years from 1 88Q 

 to 1922 and the two shorter periods from 1916 to 1922 and from 1917 

 to 1922. The forage-crop experiments at Havre cover the years 1916 

 to 1922, inclusive. The average seasonal precipitation for this 

 period (8.76 inches) and the average annual precipitation (11.72 

 inches) are about 1 inch and 1J inches less than the corresponding 

 averages for the 43-year period. In 1916, however, the precipitation 

 was abnormally high; and when this year is excluded the annual 

 average for the years from 1917 to 1922 is about 3 inches and the 

 seasonal average 2 inches less than the averages for the long period. 

 About 75 per cent of the total precipitation occurs during the growing 

 season. The greatest annual precipitation was 25.67 inches, in 1884, 

 and the least 6.76 inches, in 1905. The average monthly evapora- 

 tion ° in inches during the past seven years was approximately as 

 follows: April, 3.4; May, 5.8; June, 7; July, 8; August, 7.2; 'and 

 September, 4.4; a seasonal average of nearly 36 inches. 4 This is a 

 ratio of precipitation to evaporation of 1 to 4. 



Table 3. — Monthly, seasonal, and annual precipitation at Havre, Mont., during 

 the years 1915 to 1922, with averages for certain years. 



[Data (in inches) from the records of the United States Weather Bureau and of the Biophysical Labora- 









tory of the Bureau of Plant Industry.] 





















1 















Sea- 































sonal. 





Year. 



Jan. 



Feb. 



Alar. 



Apr. 



May. 



Tune. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Apr. 



to 



Sept. 



Total. 































1915 



0.67 



0.44 



0.10 



0.24 



1.95 



3.35 



3.17 



0.94 



2.05 



0. 42 



0.12 



0.77 



11.70 



14.22 



1916 



1.75 



.47 



.59 



.57 



2.69 



4.32 



5.20 



.20 



1.90 



.82 



.15 



.58 



14.88 



19.24 



1917 



.51 



.20 



.04 



.86 



.42 



1.59 



.43 



.70 



5.33 



.38 



.08 



1.32 



9. 33 



11. Hi 



1918 



.75 



.25 



.40 



.44 



.08 



1.51 



.74 



2.10 



.64 



1.17 



.42 



.05 



5.51 



S.55 



1919 



.38 



.56 



.50 



.31 



1.09 



1.99 



.19 



.60 



.07 



.48 



. 56 



.23 



4. 85 



7.56 



1920 



.88 



.30 



.40 



1.71 



1.39 



2.20 



1.36 



1.26 



.35 



1.04 



.01 



.30 



s. 27 



11.20 



1921 



.05 



.06 



1.81 



.80 



2.83 



2.68 



2.16 



.53 



1.45 



.19 



.70 



.11 



10.45 



13.37 



1922 



.19 



.76 



.27 



1.43 



2.37 



.90 



1.90 



.92 



.54 



.11 



.31 



.56 



8. 06 



10.26 







Average: 

 1915 to 1922. 



.65 



.38 



.51 



.80 



1.60 



2.32 



1.89 



.91 



1.62 



.58 



.29 



.49 



9.13 



12.03 



Crop years, 































1916 to 































1922 



.04 



.37 



.57 



.87 



1.55 



2.17 



1.71 



.91 



1.55 



.60 



.32 



.45 



8. 70 



11.72 



1917 to 1922. 



.46 



. 36 



.57 



.92 



1.36 



1.81 



1.13 



1.02 



1.50 



. 56 



.35 



.43 



7.74 



10.47 



43 years, 































1880 to 































1922 



.74 



.48 



.51 



.88 



1.92 



2.72 



1.79 



1.20 



1.27 



.66 



.60 



.51 



9. 78 



13.21 



Table 4. — Dates of killing frosts, the last in spring and the first in fall, with frost- 

 free period at the Northern Montana Substation, Havre, Mont., in each year 

 from 1910 to 1922, inclusive. 



[Data from the records of the United States Weather Bureau.] 



Year. 



Last in 



spring. 



First in 

 fall. 



Frost- 

 free 



period. 



Year. 



Last in 

 spring. 



First in 

 fall. 



Frost- 



free 

 period. 



1910 



June 3 

 Apr. 30 

 Mav L3 



May 2ii 

 Mas 13 

 Mav 20 

 Mav II 

 June 3 



Aug. 25 



A.m. 27 



Sept. 15 

 Sept. ii 

 Oct 12 

 Sept. ii 

 Sept. 1 1 



Oct. II 



Dai) ft. 

 ' S3 

 119 

 125 

 114 

 152 

 117 

 123 



130 



1918 



.lime :; 

 Ma\ 11 



Sept. o 



Sept. 20 



Days. 



191 1... 



1010 



138 



1912 



1913 



1920 



1021 



Mav 1 

 Mav 3 

 May It 



...do Its 



Sept. 11 131 

 Oct. o i it:. 



191 1 



1922 



Average, 1910 tol922 







1916.................. 



Mav 17 



Ocl 19 

 Oct. 16 



125 



1917 



Average, L899to 1909 Ma\ 



123 









- 



The '■'. iporatiqo la recorded by measuring the open water surface in a tank sunk In the ground al abotq 

 iihe Biophysical Lahoratorj ofthe Bureau ol riant industry. 



i 0" general ground le\ 



■ i mm i in- record 



