Thermograph

How unusual is the weather? Graded against ~45 years of local climate history.

Boise weather records

Record high and low temperatures for Boise, by month, by season, and all-time, with the dates they occurred, across 1980–2026 of daily climate history. Its hottest day on record reached 109°F on 2002-07-11; its coldest fell to -25°F on 1990-12-22.

Records by month

The warmest (▲) and coldest (▼) both the daytime high and the overnight low have ever been in each calendar month, so each column shows its record high and its record low. Tap a month for its full averages and typical range.

MonthDaytime highOvernight low
January
62°F2024-01-31
10°F1991-01-04
48°F1997-01-01
-7°F2017-01-07
February
68°F1986-02-24
10°F1989-02-05
54°F2015-02-06
-13°F1985-02-04
March
83°F2026-03-21
32°F1993-03-01
56°F1987-03-05
13°F1993-03-01
April
92°F2012-04-23
42°F2024-04-05
62°F1987-04-28
24°F1999-04-02
May
101°F2003-05-28
48°F1983-05-09
71°F2009-05-19
29°F2022-05-10
June
108°F2015-06-28
54°F1980-06-02
79°F2021-06-30
37°F1984-06-01
July
109°F2002-07-11
67°F1983-07-02
82°F2005-07-22
42°F1986-07-05
August
108°F2018-08-10
62°F1989-08-24
79°F2004-08-02
41°F1992-08-25
September
104°F2022-09-03
53°F1986-09-27
74°F1998-09-05
31°F1984-09-25
October
94°F1992-10-01
35°F2002-10-31
66°F1992-10-01
14°F2019-10-30
November
74°F2020-11-05
19°F1985-11-26
58°F1999-11-08
-2°F2014-11-16
December
61°F2025-12-10
-8°F1990-12-22
55°F2014-12-12
-25°F1990-12-22

Records by season

The warmest (▲) and coldest (▼) both the daytime high and the overnight low have reached in each meteorological season (Northern Hemisphere, each a three-month span).

SeasonDaytime highOvernight low
Winter (Dec–Feb)
68°F1986-02-24
-8°F1990-12-22
55°F2014-12-12
-25°F1990-12-22
Spring (Mar–May)
101°F2003-05-28
32°F1993-03-01
71°F2009-05-19
13°F1993-03-01
Summer (Jun–Aug)
109°F2002-07-11
54°F1980-06-02
82°F2005-07-22
37°F1984-06-01
Autumn (Sep–Nov)
104°F2022-09-03
19°F1985-11-26
74°F1998-09-05
-2°F2014-11-16

All-time records

The most extreme value Boise has recorded for each metric across its entire history.

High

Highest 109°F 2002-07-11
Lowest -8°F 1990-12-22

Low

Highest 82°F 2005-07-22
Lowest -25°F 1990-12-22

Feels-like

Highest 116°F 1998-07-18
Lowest -45°F 1990-12-22

Humidity

Highest 18.7 g/m³ 2021-08-01
Lowest 0.4 g/m³ 1990-12-22

Wind

Highest 30 mph 1999-08-31
Lowest 3 mph 1996-10-30

Gust

Highest 54 mph 2012-06-05
Lowest 5 mph 1984-01-06

Precip

Wettest 1.23 in 2005-05-16
Driest 33-day dry spell 1981-07-08

For rainfall, the “driest” figure is the longest run of consecutive days without measurable rain, dated to when that dry spell began.

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