19 



Average trmperatuirx, lSSO-1902. 



Octol)er •*-• 2 



November -^-'^ 



December --■ 1 



January ^''^- - 



February -0. S 



March ^1- -1 



In the period imdor consideration there have been spells of intense 

 cold. Five tiiiu s in twenty-two years the mercury has gone below 

 — iO . and or. .lamiary 14, isss, it re^ifistered — 5(t^. On the other 

 hand, the winter of 1!H»L was unusually mild and the lowest record 

 was —14^. 



The valley, for the most part l)eino- surrounded by mountains, is not 

 subject to hiuh winds. The lowest temperature is usually reached in 

 a calm, (dear night. The period of severe cold seldom lasts long. 

 Rarely does the average minimum temperature for any winter month 

 fall below zero, and on an average the temperature of 92.5 per cent of 

 all the days in the year is above zero. 



From the farmer's standpoint the worst feature of the climate is 

 the comparativ(dy short season between the late spring and the early 

 autunjn frosts. Frosts always occur in May and September. In ten 

 out of the twenty-two years covered by the record there have been 

 frosts in June; in one year there was frost in July, and in five years 

 there were frosts in August. Of the frosts in June. July, and August 

 70 per cent have either been 2^ or less of frost. Inasmuch as mo.-t 

 plants can resist at least 1^ below freezing it follows that the injuri- 

 ous effects of low temperature during the months named have not been 

 great. Only once in twenty-two years has there been no frost in Sep- 

 tember. The September freeze may occur early in the month, in 

 which case it occasionally injures late-sown wheat. 



WEST GALLATIN RIVER. 



This stream is by far the largest and most important tributary of 

 the Gallatin drainage system. From its source in the northwest cor- 

 ner of the Yellowstone National Park it takes a northerly course in 

 general, and for the first 65 miles of its course is confined to rough, 

 mountainous country. At this point it leaves its canyon and enters 

 the broad Gallatin Valley, through the western portion of which it 

 takes a slight northwesterly course to the northern extremity of the 

 valley, where it is joined by the East Gallatin River, flows westerly 

 for a distance of 8 or 9 miles, and joins the Madison and Jefferson 

 rivers at Three Forks, the three streams forming the upper Missouri 

 River. 



The drainage area of the West Gallatin River contains approxi- 

 mately 1,200 square miles. This area includes the basin of the river's 



