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Boise, ID Weather by Month and Climate Averages
Monthly normals · Rain · Snow
Sunshine · Freeze dates · Records · Best time to visit
What is the weather like in Boise, ID?
Boise, ID gets 11.5 in of precipitation a year over about 89 rainy days, and about 17.6 in of snow a season. July is the warmest month (average high 92°F) and January the coldest (average low 25°F).
Semi-arid climate
Boise, ID has hot summers and chilly winters. Daytime highs range from about 39°F in December to 92°F in July. December is usually the wettest month, and snow falls in winter. The most comfortable time to visit is typically April to May and September to October, when daytime highs sit near 70°F.
| Season | Months | Avg low | Avg high |
|---|---|---|---|
| Winter | Dec–Feb | 26° | 41° |
| Spring | Mar–May | 40° | 63° |
| Summer | Jun–Aug | 59° | 88° |
| Autumn | Sep–Nov | 42° | 65° |
How much rain does Boise get?
Boise gets 11.5 in of precipitation in an average year, spread over about 89 days with measurable rain. That is more rainy days than 51% of the US.
December is the wettest month, with 1.5 in. August is the driest, with 0.2 in. December has the most rainy days, about 12.
The longest dry spell in the last five years lasted 50 days, to August 1, 2022.
From September 2025 to August 2026 Boise got 13.1 in of rain, against a normal of 11.5 in for those months. April 2026 had the most, with 4.2 in.
See where Boise ranks: rainiest cities in the US, US cities with the most rainy days.
Does it snow in Boise?
Yes. Boise gets about 17.6 in of snow in an average season, measured at the reporting station.
The snowiest winter on record is 1985–86, with 39.6 in.
The most recent measurable snow at the station fell on April 2, 2026.
From September 2025 to August 2026 the station measured 1.8 in of snow, against a normal of 17.6 in for those months. February 2026 had the most, with 1.0 in.
See where Boise ranks: snowiest cities in the US.
Boise weather by month
Boise weather in January
In January, Boise averages a high of 39°F and a low of 25°F. It gets 1.4 in of precipitation over about 11 rainy days. Estimated sunshine is 36% of daylight hours, derived from ERA5 cloud cover. The January record high is 66°F (2024) and the record low is -14°F (1977).
Boise weather in February
In February, Boise averages a high of 46°F and a low of 29°F. It gets 1.0 in of precipitation over about 9 rainy days. Estimated sunshine is 48% of daylight hours, derived from ERA5 cloud cover. The February record high is 71°F (1992) and the record low is -15°F (1989).
Boise weather in March
In March, Boise averages a high of 55°F and a low of 34°F. It gets 1.3 in of precipitation over about 10 rainy days. Estimated sunshine is 46% of daylight hours, derived from ERA5 cloud cover. The March record high is 83°F (2026) and the record low is 6°F (1971).
Boise weather in April
In April, Boise averages a high of 62°F and a low of 39°F. It gets 1.2 in of precipitation over about 9 rainy days. Estimated sunshine is 52% of daylight hours, derived from ERA5 cloud cover. The April record high is 92°F (1987) and the record low is 20°F (1975). April is one of the most comfortable months to visit.
Boise weather in May
In May, Boise averages a high of 72°F and a low of 47°F. It gets 1.4 in of precipitation over about 8 rainy days. Estimated sunshine is 51% of daylight hours, derived from ERA5 cloud cover. The May record high is 100°F (2025) and the record low is 22°F (1982). May is one of the most comfortable months to visit.
Boise weather in June
In June, Boise averages a high of 81°F and a low of 54°F. It gets 0.8 in of precipitation over about 5 rainy days. Estimated sunshine is 61% of daylight hours, derived from ERA5 cloud cover. The June record high is 110°F (2015) and the record low is 31°F (1984).
Boise weather in July
In July, Boise averages a high of 92°F and a low of 61°F. It gets 0.2 in of precipitation over about 2 rainy days. Estimated sunshine is 84% of daylight hours, derived from ERA5 cloud cover. The July record high is 110°F (2013) and the record low is 35°F (1986).
Boise weather in August
In August, Boise averages a high of 91°F and a low of 60°F. It gets 0.2 in of precipitation over about 2 rainy days. Estimated sunshine is 75% of daylight hours, derived from ERA5 cloud cover. The August record high is 110°F (2018) and the record low is 34°F (1992).
Boise weather in September
In September, Boise averages a high of 80°F and a low of 52°F. It gets 0.4 in of precipitation over about 4 rainy days. Estimated sunshine is 74% of daylight hours, derived from ERA5 cloud cover. The September record high is 104°F (2022) and the record low is 23°F (1970). September is one of the most comfortable months to visit.
Boise weather in October
In October, Boise averages a high of 65°F and a low of 41°F. It gets 0.8 in of precipitation over about 6 rainy days. Estimated sunshine is 63% of daylight hours, derived from ERA5 cloud cover. The October record high is 94°F (1992) and the record low is 11°F (1971). October is one of the most comfortable months to visit.
Boise weather in November
In November, Boise averages a high of 49°F and a low of 32°F. It gets 1.2 in of precipitation over about 10 rainy days. Estimated sunshine is 46% of daylight hours, derived from ERA5 cloud cover. The November record high is 78°F (1999) and the record low is -3°F (1985).
Boise weather in December
In December, Boise averages a high of 39°F and a low of 25°F. It gets 1.5 in of precipitation over about 12 rainy days. Estimated sunshine is 36% of daylight hours, derived from ERA5 cloud cover. The December record high is 63°F (1987) and the record low is -25°F (1990).
Sunshine, humidity and wind in Boise
July is the sunniest month in Boise, with estimated sunshine of 84% of daylight hours from ERA5 cloud cover. January is the cloudiest, at 36%. The annual cloud-cover estimate is 56% of daylight hours; it is not a measurement of sunshine duration. Boise is sunnier than 76% of the US.
Humidity peaks in January at 72% and is lowest in July at 25%.
Wind averages 7 mph over the year, and April is the windiest month at 9 mph.
Boise has about 52 days a year above 90°F. Boise is hotter than 70% of the US.
Thunderstorms occur on about 14 days a year.
See where Boise ranks: sunniest cities in the US, cloudiest cities in the US, hottest cities in the US.
First and last freeze in Boise
The first fall freeze in Boise typically comes around October 13, and the last spring freeze around May 4. That leaves a frost-free growing season of about 162 days.
Boise weather records
These records cover BOISE AIR TERMINAL during 1970–2026. Earlier records or other stations in the city may differ.
The hottest temperature on record at the Boise station is 110°F, on July 13, 2002. The coldest is -25°F, on December 22, 1990.
The wettest day in the available station history brought 1.8 in of precipitation, on May 29, 1990.
45 all-time records have been set at the station since 1970.
The annual mean temperature has changed by +0.8°F per decade since 1970.
The best time to visit Boise
The most comfortable time to visit is typically April to May and September to October, when daytime highs sit near 70°F.
Winter (December–February) is chilly, with average highs around 41°F and lows near 26°F. Snow is possible.
Spring (March–May) is mild, with average highs around 63°F and lows near 40°F.
Summer (June–August) is hot, with average highs around 88°F and lows near 59°F.
Autumn (September–November) is mild, with average highs around 65°F and lows near 42°F.
Monthly climate
| Month | Average low | Average high | Precip | Rain days | Wind | Humidity | Estimated sunshine | Record high | Record low |
|---|---|---|---|---|---|---|---|---|---|
| January | 25° | 39° | 1.4 in | 11 | 7 mph | 72% | 36% | 66° | -14° |
| February | 29° | 46° | 1.0 in | 9 | 8 mph | 62% | 48% | 71° | -15° |
| March | 34° | 55° | 1.3 in | 10 | 9 mph | 52% | 46% | 83° | 6° |
| April | 39° | 62° | 1.2 in | 9 | 9 mph | 38% | 52% | 92° | 20° |
| May | 47° | 72° | 1.4 in | 8 | 8 mph | 40% | 51% | 100° | 22° |
| June | 54° | 81° | 0.75 in | 5 | 8 mph | 36% | 61% | 110° | 31° |
| July | 61° | 92° | 0.21 in | 2 | 7 mph | 25% | 84% | 110° | 35° |
| August | 60° | 91° | 0.17 in | 2 | 7 mph | 30% | 75% | 110° | 34° |
| September | 52° | 80° | 0.43 in | 4 | 7 mph | 32% | 74% | 104° | 23° |
| October | 41° | 65° | 0.81 in | 6 | 7 mph | 44% | 63% | 94° | 11° |
| November | 32° | 49° | 1.2 in | 10 | 7 mph | 64% | 46% | 78° | -3° |
| December | 25° | 39° | 1.5 in | 12 | 7 mph | 72% | 36% | 63° | -25° |
Station: BOISE AIR TERMINAL, 6 km from the city. Temperature normal baseline: 1991–2020, calculated from available NOAA GHCN-Daily observations. Available station history: 1970–2026; record values refer to this station and period, not the entire city’s history. Precipitation includes rain and the water equivalent of frozen precipitation; snowfall depth is shown separately when available. Sources and methods
From ERA5 reanalysis. Sunshine is estimated from cloud cover.
Boise climate questions
How much rain does Boise get?
Boise gets 11.5 in of precipitation in an average year, over about 89 rainy days.
What is the wettest month in Boise?
December is the wettest month in Boise, with 1.5 in. August is the driest, with 0.2 in.
How many rainy days does Boise have a year?
Boise has about 89 days with measurable rain in an average year. December has the most, about 12.
Does it snow in Boise?
Yes. Boise gets about 17.6 in of snow in an average season. The snowiest winter on record is 1985–86, with 39.6 in.
What is the hottest month in Boise?
July is the warmest month in Boise, with an average high of 92°F.
What is the coldest month in Boise?
January is the coldest month in Boise, with an average low of 25°F.
What is the record high temperature in Boise?
Within the available 1970–2026 station history, the record high at the Boise station is 110°F, set on July 13, 2002. The record low is -25°F, on December 22, 1990.
What is the sunniest month in Boise?
July is the sunniest month in Boise, with estimated sunshine of 84% of daylight hours from ERA5 cloud cover. January is the cloudiest.
When is the first frost in Boise?
The first fall freeze in Boise typically comes around October 13. The last spring freeze is around May 4.
What is the best time to visit Boise?
The most comfortable time to visit is typically April to May and September to October, when daytime highs sit near 70°F.