Boise Weather History
Idaho · US States · Weather data 1976–today
Boise sits 4855km from the equator, 832m above sea level. That combination gives it a climate with cold winters, hot dry summers, and very little rain (Cold semi-arid climate). Its record high is 42.0°C, set 2003-07-23, its record low -33.5°C, set 1990-12-22.
Data through August 4, 2026.
Frequently asked questions about the weather in Boise
What is the hottest temperature ever recorded in Boise?
The highest temperature in this record for Boise is 42.0°C, measured on 2003-07-23. That is a recorded daily value from Boise's own series covering 1976 to 2025, not an estimate or a regional average.
What is the coldest temperature ever recorded in Boise?
The lowest temperature in this record for Boise is -33.5°C, measured on 1990-12-22. Together with the heat record above, that spans the full range this city has actually experienced across 1976 to 2025.
How much rain does Boise get a year?
Boise averages 339mm of precipitation a year, spread across roughly 73 days with at least 1mm. That average is taken over 50 complete calendar years, so one exceptionally wet or dry year does not set the figure.
What was the wettest day on record in Boise?
On 1979-08-13, 33.4mm fell on Boise, the highest single-day total in this series. For scale, that is roughly 10% of what the city receives in an average full year, in one day.
How many hours of sunshine does Boise get a year?
Boise averages 3773 sunshine hours a year, which works out to about 10.3 hours a day across the whole year. Sunshine hours measure the time direct sunlight actually reaches the ground, not simply how long it is light.
How warm are summers and how cold are winters in Boise?
Across the summer months Boise averages a daytime high near 30.4°C, while winter nights average -4.1°C. The seasons here are set from Boise's position relative to the equator rather than a fixed northern-hemisphere calendar.
What is the strongest wind recorded in Boise?
The strongest wind speed recorded in Boise is 56 km/h, on 2021-03-29. That is the daily maximum sustained wind rather than the peak gust, which typically runs higher still.
