Boise, Idaho – Drivers and outdoor crews across southwest Idaho will see a rapid temperature swing within the next 24 hours, with highs pushing near 75°F by Tuesday afternoon before winds and cooler air move in overnight.
According to the National Weather Service in Boise, above-normal temperatures will peak Tuesday, with Boise, Meridian, and Nampa reaching the low to mid-70s by 4 p.m. Tuesday. A cold front arrives late Tuesday night, bringing increasing winds and scattered mountain showers through Wednesday morning.
Across the Treasure Valley, calm and dry conditions Tuesday will give way to gusty winds after 10 p.m., especially along I-84 between Caldwell and Mountain Home. In higher elevations like McCall and Stanley, precipitation chances climb to 50–60% Tuesday evening, with brief showers impacting visibility on mountain passes including Banner Summit.
The rapid warmup may draw people to rivers and reservoirs, but water temperatures remain dangerously cold, near 60°F or lower. Anyone recreating on the water should wear a life jacket and cold-water gear to reduce shock risk.
Conditions turn cooler by Wednesday afternoon, with highs dropping back into the upper 50s to near 60°F. Additional advisories may be issued as the system moves through midweek.
