Idaho local data guide

Boise, Idaho Weather Overview

Boise, Idaho features a semi-arid climate characterized by four distinct seasons: hot, dry summers and cold, snowy winters. As of July 20, 2026, the region is experiencing intense summer heat, with high temperatures frequently reaching the upper 90s to low 100s, alongside air quality challenges stemming from regional wildfire activity.

Updated with grounded research as of 2026-07-20.

The short answer

Boise, Idaho experiences a semi-arid climate with distinct seasonal shifts. Residents encounter hot, dry summers often exceeding 90°F, and cold, snowy winters. Climatological data is tracked using the 1991–2020 normal period at the Boise Air Terminal (KBOI).

Key facts

Current Normal Temperature Range (July 20, 2026)
Normal high of 94°F and normal low of 63°F.
Average Annual Snowfall
17.6 inches (based on 1991–2020 climate normals).
Climate Normal Period
1991–2020

Seasonal Temperature Patterns

Boise’s climate is defined by significant temperature variations throughout the year. Summers are typically hot and arid, with high temperatures frequently peaking above 90°F. As of mid-July 2026, the region has been subject to heat advisories with temperatures reaching as high as 103°F. Winters are characterized by cold conditions, during which freezing temperatures are common, though the area does not typically experience the prolonged, extreme sub-zero cold found in higher elevations of the Rocky Mountains.

Precipitation and Winter Snowfall

The Boise region receives an average annual snowfall of approximately 17.6 inches based on the current 1991–2020 climate normals. Snowfall is most common between late November and early February. While urban areas in the valley often experience manageable snow accumulation that is cleared by municipal services, the nearby foothills and local ski areas like Bogus Basin receive significantly higher amounts of annual snowfall.

Air Quality and Wildfire Season

During the summer months, Boise’s air quality is periodically impacted by wildfire smoke. Wildfires within Idaho or elsewhere in the Western U.S. can transport fine particulate matter (PM2.5) into the Treasure Valley, leading to temporary air quality alerts. Residents are advised to monitor the Idaho Department of Environmental Quality and official weather channels during the summer wildfire season, as air quality levels can fluctuate between 'moderate' and 'unhealthy' depending on fire activity and wind patterns.

Common questions

What is the average annual snowfall in Boise?

The 1991–2020 climate normal for annual snowfall at the Boise Air Terminal is 17.6 inches.

How does Boise's air quality typically fluctuate during the summer wildfire season?

Boise frequently experiences poor air quality during the summer due to wildfire smoke. While air quality is often 'good' or 'moderate,' smoke from regional fires can push levels into the 'unhealthy' range, particularly for sensitive groups.

Related Idaho questions

  • What is the average annual snowfall in Boise?
  • How does Boise's air quality typically fluctuate during the summer wildfire season?
  • Where can I find historical climate data for Boise, Idaho?

Sources and verification