38 



MONTANA: INDUSTRIAL RESOURCES 



creasod procipitatlon comes at an opportune time, affording .sufficient moisture 

 to germinate fall-sowed crops, to revive pastures and stubble fields, and to permit 

 fall plowing. Rarely does it interfere with digging of potatoes and other root 

 crops. 



October — when the peak of crop marketing is reached in Montana — has an 

 average precipitation of .99 inches, distributeil over a period of three to six days. 

 The roads are firm and the average temperature (44.6 degrees) is .iust right to 

 permit teams to exert their greatest efforts. October is also a busy month for plow- 

 ing, (the September precipitation normally being retained in the soil) ; for getting 

 in a year's supply of fuel — wood from the mountains in the western part of the 

 state, and in tlu^ eastern part of the state lignite or sub-bituminous coal from the 

 niunerous coal banks that abound. Favored, indeed, is the Montana farmer by 

 October climatic conditions. 



Violent local storms are exceedingly rare, says Bulletin Q of the United States 

 Weather Bureau, and practically the onl.v climatic element causing directly the 

 loss of life or i)roperty is the high northerly wind with rain or snow and freezing 

 temperature, and losses from this cause, which are confined mostly to the eastern 

 plains, are in a great measure preventable, if not wholly so. 



In the articles descriptive of the counties climatolo.gical data are given for 



all l)nt Treasure and Daniels counties. The longest growing season is l.")0 days, 



found at Miles City, in eastern ^Montana, and at Kali.spell, in 



Frost Free northwestern Montana, on the western side of the moiuitains. 



Days The number of days in the growing season does not tell the 



Heat Units whole story, however. An important factor is the number of 



heat units during the frost free period. A heat unit, as the 



term is used in agriculture, is each degree of mean temperature above 40° F. 



between the last killing frost in the spring and the first killing frost in the fall. 



Normal daily tempei-atures are available at only four places in the state — Miles 



City, Kalispell, Havre and Helena. During the growing .season at Miles City there 



are 3,843 heat units while at Kalispell there are 2.716 heat units over the same 



number of frost free days. The growing season at Havre is 126 days and at 



Helena 142 days, but both stations have the same number of heat luiits — 3,006. 



Some crops will do better under Havre conditions with its shorter growing season 



but more intense heat than they will at Helena with a longer growing season but 



less inten.se heat, and vice versa. 



Another important factor, according to plant pathologists, besides the length 

 of the growing season and the niunber of heat units, is the number of hours of 

 sunlight. No state has a larger possible number of hours of sunshine than has 

 Montana. The state is also fortunate in that, in this northerly latitude, its long- 

 est da.vs occur during the growing season and the highest percentage of the pos- 

 sible hours of sunshine is attained during this same season. Referring to the 

 effect of sinilight on crops, the United States Department of Agriculture says, 

 "This princii)le affords the clue to the fact that man.v plants grow most lux- 

 uriantl.v near the northern limit of their range. The long northern da.v allows 

 them to attain their maximum growth before the shorter day intervenes to check 

 vegetative growth and start the reproductive process."' 



MONTANA AVEATHER* 



♦Based on records coveringr 1895 to 1922 inclusive. 



