Idaho enjoys a four-season climate, but weather conditions can be unpredictable, especially in the higher elevations of the mountains.
Along the Snake River Plain (or Valley) summers are generally warm (seldom hot). Evenings are cool, and July and August are considered perfect by most. In late fall the weather is much cooler and winter conditions can be snowy and much colder.
Across the southern reaches of the Snake River Plain summer high temperatures average near 75 degrees, while winter highs are in the low-40s. The average annual rainfall here approaches 26 inches.
In the mountains across the entire state weather conditions are cooler throughout the year, with cold and snowy conditions fall and winter.
The average summer high temperature across the State of Idaho is right at 64 degrees, dropping to around 30 degrees in winter.
The average rainfall in the higher elevations of the Rockies (central and north) exceeds 60 inches, and snowfall is usually heavy. For an interesting look at Idaho precipitation levels, view this precipitation map.
Seasonal Temperature Averages:
In these selected cities....
High Temperatures ( Fahrenheit/Celsius )
(Jan) 37/3 (Feb) 40/4 (Mar) 49/9 (Apr) 58/14
(May) 67/19 (Jun) 77/25 (Jul) 87/30 (Aug) 91/33
(Sep) 84/29 (Oct) 71/22 (Nov) 57/14 (Dec) 41/5
Low Temperatures ( Fahrenheit/Celsius )
(Jan) 23/-5 (Feb) 27/-3 (Mar) 31/0 (Apr) 37/3
(May) 43/6 (Jun) 51/10 (Jul) 59/15 (Aug) 62/17
(Sep) 58/14 (Oct) 48/9 (Nov) 38/3 (Dec) 28/2
Current Weather Conditions: