Weather & Air Quality

The Treasure Valley has a high-desert climate that surprises people. Summers run hot and dry — daytime highs in Boise routinely sit in the upper 90s in July, and the valley floor can hit triple digits while the Boise Foothills, just a few hundred feet higher, stay noticeably cooler. Winters are colder and snowier than first-time visitors expect, with overnight lows in the teens and the occasional "inversion" week where cold, polluted air settles in the valley while it's clear and sunny up on Bogus Basin. Spring and fall are short, mild, and the best times to be outside.

Two seasonal hazards dominate local weather. From late July through September, smoke from regional wildfires can push the air quality index from "Good" into "Unhealthy" or worse for days at a time — schools cancel outdoor practice, joggers move to treadmills, and you watch the wind direction. In winter, valley inversions can do the same to particulate levels, prompting voluntary wood-burning bans. Spring brings pollen season, with tree pollen peaking in March–April and grass pollen following in May–June.

Below you'll find the live widgets we trust for a quick read on conditions, plus links to the authoritative sources for forecasts, air quality, river and reservoir levels, and seasonal warnings.