What is the hottest month in Boise?

July — average highs around 96° with lows near 65°.

What is the coldest month in Boise?

January, when nights typically drop to 27° and days top out near 41°.

What is the rainiest month in Boise?

December, averaging about 2.4 in of precipitation; the driest is July at roughly 0.1 in.

How warm is Boise over the year?

The annual mean is 54°, with about 15 in of precipitation in a typical year (1991-2020 normals).

Boise Climate — Monthly Normals 1991-2020

Climate in Boise

The typical year in Boise (Idaho), from 1991-2020 normals. For what's happening now, see the current forecast; a month ahead — the 30-day outlook.

Annual mean temp

12.4°C

average across 12 months

Annual precipitation

389 mm

yearly total

Warmest month

Jul

⌀ max 35°C

Coldest month

Jan

⌀ min -2°C

Temperatures by month

typical high (orange) · typical low (blue)

Jan

-3° … 5°

Feb

-3° … 7°

Mar

1° … 12°

Apr

4° … 17°

May

9° … 23°

Jun

13° … 29°

Jul

19° … 35°

Aug

18° … 34°

Sep

13° … 29°

Oct

6° … 19°

Nov

0° … 10°

Dec

-2° … 5°

Precipitation by month

monthly totals across the year

Jan

50 mm

Feb

53 mm

Mar

45 mm

Apr

29 mm

May

46 mm

Jun

22 mm

Jul

2 mm

Aug

6 mm

Sep

11 mm

Oct

26 mm

Nov

37 mm

Dec

62 mm

The short version

RegionIdaho

Latitude43.6135°N

Annual mean12.4°C

Annual precipitation389 mm

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Weather map — Boise

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Source · 1991-2020 normals

Boise, ID Climate