ClimateAverages

Boise Climate

Idaho, United States of America · population 145,987 · 281 weather stations within 200 km · records 1837 to 2025

Average annual daytime high
15.8°C
Warmest month · July
31.0°C
Typical daytime high
Coldest month · January
-7.0°C
Typical overnight low

Boise has an average annual daytime high of 15.8°C, based on the 1951 to 1980 baseline. Its warmest month is July, when highs typically reach 31.0°C, and its coldest is January, with overnight lows near -7.0°C.

Month by month averages

MonthAvg highAvg low
January1.3°C-7.0°CColdest
February5.6°C-4.4°C
March9.9°C-2.4°C
April15.2°C1.0°C
May20.6°C5.3°C
June25.2°C8.9°C
July31.0°C12.1°CWarmest
August29.8°C11.3°C
September24.6°C7.0°C
October17.0°C1.9°C
November7.7°C-2.4°C
December2.3°C-5.5°C

Temperature range across the year

-9°2°12°22°33°JanFebMarAprMayJunJulAugSepOctNovDec
Daytime high Overnight low
Hottest year on record
1933
+2.2°C vs. 1951–1980
Coldest year on record
1837
-2.7°C vs. 1951–1980

These figures reflect annual averages, not single-day records. Daily observations are outside this dataset's precision.

Is Boise getting hotter?

Since 1900, Boise's average temperature has risen by +1.4°C. Compared to the earliest station records that begin in 1837, warming totals +2.1°C.

8.2°8.7°9.3°9.8°10.3°1951–1980 baseline190019251950197520002025

20-year smoothed annual temperature reconstructed from station anomalies. Dashed line: 1951–1980 baseline.

Best time to visit
April to October

Daytime highs sit within a comfortable 15°C to 26°C range.

FAQ

What is the average temperature in Boise?

Boise's average annual daytime high is 15.8°C, based on the 1951 to 1980 baseline period. The warmest month is July, with highs averaging 31.0°C, and the coldest is January, with lows averaging -7.0°C.

What is the warmest month in Boise?

July is the warmest month in Boise, with typical daytime highs of 31.0°C.

What is the hottest year on record for Boise?

1933 is the hottest year on record for Boise, running +2.2°C above the 1951 to 1980 baseline.

Is Boise getting hotter?

Yes. Since 1900, Boise has warmed by roughly +1.4°C.

When is the best time to visit Boise?

April to October typically offers the most comfortable daytime highs, in the 15°C to 26°C range.

Nearby cities

Baseline period 1951 to 1980. Monthly averages are the mean of station observations weighted by proximity. Warming trend is the 20-year smoothed anomaly against that baseline.