Idaho greets the morning under clear skies, but the air feels heavy and still. Smoke and exhaust linger near the ground, settling into the Treasure Valley as calm winds refuse to stir things up.
According to the National Weather Service in Boise, an Air Stagnation Advisory remains in effect through early Tuesday morning. Light winds and a strong temperature inversion are trapping pollutants close to the surface across southwest and south-central Idaho, including Boise. Air quality may gradually worsen, especially during morning and evening hours.
People with asthma, heart disease, or other respiratory conditions should take precautions today. Limit prolonged outdoor activity if symptoms flare. For now, residents are urged to reduce emissions when possible, including limiting wood burning and unnecessary driving.
Temperatures stay mild for mid-December. Boise warms into the low 50s today and Monday, with sunshine filtering through the stagnant air. While it feels pleasant, the lack of wind allows pollution to build instead of disperse.
Changes arrive by Tuesday as moisture increases. Clouds thicken and rain chances rise during the afternoon and evening. That incoming system may finally help scrub the air, but it introduces new travel concerns. Wet roads could turn slick at night as temperatures dip into the 30s, raising early black ice risks.
By Wednesday, rain becomes more likely, with snow mixing in during cooler periods. Winds increase slightly, improving air quality but creating patchy slick spots during morning commutes. Late-week systems continue the unsettled trend, with periods of rain and snow possible into Friday.
As Christmas travel ramps up, residents should stay alert to rapid changes. Calm, mild mornings may give way to damp, slippery conditions later in the week.
5-Day Outlook for Boise, ID
• Today: Sunny. High near 52°. Air Stagnation Advisory.
• Monday: Partly sunny. High near 51°.
• Tuesday: Chance of rain. High near 56°.
• Wednesday: Rain likely, snow possible later. High near 53°.
• Thursday: Rain and snow possible. High near 47°.
