Thermograph

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

Boise, Idaho, United States weather records

Record high and low temperatures for Boise, Idaho, United States, by month, by season, and all-time, with the dates they occurred, across 1981–2026 of daily climate history. Its hottest day on record reached 110°F on 2002-07-12; its coldest fell to -15°F on 1990-12-29.

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
58°F2024-01-31
8°F1982-01-06
41°F2003-01-31
-9°F2017-01-07
February
65°F1995-02-24
10°F1989-02-04
42°F2015-02-06
-9°F1989-02-05
March
80°F2026-03-20
28°F1989-03-03
52°F2026-03-20
14°F1989-03-03
April
87°F1992-04-29
37°F2023-04-03
57°F1987-04-28
22°F1997-04-02
May
100°F2003-05-28
42°F2022-05-09
66°F1986-05-31
25°F1999-05-10
June
108°F2015-06-28
48°F1981-06-13
76°F2015-06-29
35°F1981-06-14
July
110°F2002-07-12
63°F1982-07-01
77°F2002-07-12
42°F1986-07-05
August
108°F2018-08-10
58°F1989-08-24
78°F2024-08-03
41°F1992-08-24
September
104°F2022-09-06
50°F1986-09-25
73°F1998-09-05
30°F1985-09-29
October
92°F2010-10-02
33°F2019-10-29
64°F2010-10-02
18°F2002-10-31
November
74°F1999-11-06
18°F2010-11-24
53°F1999-11-07
4°F1985-11-23
December
60°F2021-12-01
-1°F1990-12-29
46°F2014-12-11
-15°F1990-12-29

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)
65°F1995-02-24
-1°F1990-12-29
46°F2014-12-11
-15°F1990-12-29
Spring (Mar–May)
100°F2003-05-28
28°F1989-03-03
66°F1986-05-31
14°F1989-03-03
Summer (Jun–Aug)
110°F2002-07-12
48°F1981-06-13
78°F2024-08-03
35°F1981-06-14
Autumn (Sep–Nov)
104°F2022-09-06
18°F2010-11-24
73°F1998-09-05
4°F1985-11-23

All-time records

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

High

Highest 110°F 2002-07-12
Lowest -1°F 1990-12-29

Low

Highest 78°F 2024-08-03
Lowest -15°F 1990-12-29

Feels-like

Highest 119°F 2015-06-28
Lowest -38°F 1990-12-29

Humidity

Highest 15.9 g/m³ 2021-08-01
Lowest 0.6 g/m³ 1990-12-29

Wind

Highest 39 mph 2001-11-24
Lowest 2 mph 2009-01-15

Precip

Wettest 1.14 in 2025-12-21
Driest 66-day dry spell 1987-08-24

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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