The Lrrigation Problem in Montana. 219 
The remaining 10,000,000 acres may be classed as barren and 
rugged mountain peaks and some little barren “bad lands” near 
the southeastern corner of the State, and the broken and rough 
_cut banks of rivers, “ couleés,”’ etc. 
It is in these more rugged mountain regions that the great 
gold, silver and copper deposits are found. 
CLIMATE. 
The climate of Montana is far more moderate and agreeable 
than is generally supposed, the spring and fall months in the val- 
leys, which are the principal inhabited and cultivated portions, 
being delightfully mild and pleasant, with frost generally only at 
night, though these last till May and begin in early October. 
The accompanying table shows the dates of the first and last 
killing frosts at Helena, also the mean monthly temperature at 
Helena, which place is chosen as a typical station, its altitude 
being 4,262 feet. From this table, which extends over a period 
of ten years, from 1880 to 1889, inclusive, with few interruptions, 
it appears that the earliest killing frost occurred on September 
6th, 1881, and the latest killing frost on May 3d, 1888, but these 
were very exceptional frosts, the average dates for the same 
periods being September 26th and April 26th. The maximum 
temperature during the same period occurred in July, 1886, and 
was 103 degrees in the shade, while no other year showed a higher 
temperature than 97 degrees ; and the average maximum tem- 
perature for the ten years was 94 degrees. The minimum 
temperature for the same period was —40 degrees, occurring in 
February, 1887, while the average minimum for ten years was 
—29 degrees. Great ranges of temperature are sometimes expe- 
rienced, however, especially in local areas in the higher mountain 
valleys, where unusual frosts and snow flurries have occurred, 
though rarely, killing potatoes and other tender crops even in 
July and August. 
On September 5th of this year in the upper Madison Valley 
above 6500 feet of elevation, a temperature was experienced in 
the forenoon of 70 degrees, while at about 8 o’clock on the same 
evening, a snow squall occurred during which the thermometer 
must have fallen several degrees below the freezing point; by 9 
o’clock on the following morning all of the snow had disappeared 
and the temperature had greatly moderated. 
