Idaho local data guide
Average Annual Snowfall in Boise, Idaho
Based on official 1991–2020 climate normals from the National Weather Service, Boise receives an average annual snowfall of 17.6 inches at the Boise Air Terminal. This figure represents long-term averages for the valley floor, though residents should expect significant year-to-year variability and distinct differences in accumulation based on elevation and local topography.
Updated with grounded research as of 2026-07-20.
The short answer
Boise, Idaho, experiences an average annual snowfall of 17.6 inches, as measured at the Boise Air Terminal reporting station. This long-term climate normal, calculated for the 1991–2020 period, serves as a baseline for the city's valley-floor climate; however, actual snowfall totals can vary significantly between individual years due to regional weather patterns.
Key facts
- Average Annual Snowfall (1991-2020)
- 17.6 inches
- Primary Reporting Station
- Boise Air Terminal (Gowen Field)
Understanding Local Variability
Snowfall in the Treasure Valley is rarely consistent. Because of the area's U-shaped valley topography, snow accumulation can differ substantially even across short distances. Official reporting at the Boise Air Terminal may not fully represent conditions in higher-elevation neighborhoods or the surrounding foothills, which often receive more significant precipitation and cooler temperatures.
The Rain Shadow Effect
Boise’s location is influenced by the 'rain shadow effect' created by surrounding mountain ranges, such as the Owyhee Mountains. As storms move over these ranges, they often release moisture as snow in the higher terrain while losing intensity as the air descends into the Treasure Valley. This geographic phenomenon explains why heavy storms forecasted for the region may result in limited snow accumulation on the valley floor compared to the nearby mountains.
Seasonal Expectations
While 17.6 inches is the official 30-year average, individual winters can fluctuate widely. For example, some years may see very little accumulation, while others—often influenced by specific atmospheric conditions—can produce double or triple the seasonal average. Residents should plan for occasional, albeit typically short-lived, snow cover and potential travel disruptions during the peak winter months of December and January.
Common questions
Does it snow every year in Boise?
Yes, Boise receives snowfall annually, though the amount and duration of snow cover on the ground vary significantly from year to year.
How does elevation affect snow in the Treasure Valley?
Higher elevations within and surrounding the Boise area generally experience cooler temperatures and higher snowfall totals than the central valley floor where the airport is located.
Related Idaho questions
- What was the snowiest winter on record in Boise?
- How does Boise's snowfall differ from the surrounding mountain foothills?
- What is the average annual precipitation in Boise?