NOAA NCEI Climate Normals 1991–2020
Idaho Weather by Month
Temperature, rain and the hurricane season at 64 Idaho stations, month by month.
Data: NOAA NHC HURDAT2 and NOAA SPC tornado and hail reports, through 2025 · Updated
The median station records 13.2 inches of precipitation a year; Lowell Three Rivers, ID records the most, 39.6 inches, and Challis Airport, ID the least, 7.0 (5.7 times as much). July is the hottest month at the median station (average high 87°F); the hottest July is at Glenns Ferry, ID, 99°F. December is the coldest (average low 22°F); the coldest December nights are at Ketchum Rs, ID, 9°F. Highs reach 90°F on 29 days a year at the median station and on 82 at Glenns Ferry, ID, the most. Snowfall is heaviest at Ketchum Rs, ID, 102.0 inches a year.
This page compares the 1991–2020 NOAA climate normals of 64 Idaho weather stations, each the nearest station with full normals to at least one of the 90 Idaho cities on this site that have one within 25 miles.
At the median station, May is the wettest month (1.8 inches) and July the driest (0.5). Station by station, the wettest month is May at 33, December at 17 and January at 6 of the 64, and the driest July at 40, August at 22 and January at 1. The gap between the wettest and driest station is widest in January: 4.5 inches.
Month by month across Idaho
High, low and precipitation are the median of the 64 stations; the station columns name the station with the highest average high, the lowest average low, and the most and least precipitation that month, each linked to the city page it serves. Source: NOAA NCEI U.S. Climate Normals 1991–2020.
Idaho cities and their stations
How stations are matched to cities and what normals are: methodology · other states by month