Boise, Idaho – Dangerous summer heat will blanket southwest Idaho through early next week, with Boise, Caldwell, and Nampa all heading for highs near 100°F by Tuesday, July 29. Residents should prepare for prolonged daytime temperatures in the mid to upper 90s, raising the risk of heat illness and power demand surges.
According to the National Weather Service in Boise, most cities—including Mountain Home, Meridian, and Ontario—will see temperatures peaking in the mid-90s to near 100°F through Tuesday, July 29. Morning lows will offer little relief, holding in the upper 50s to mid-60s. The hottest period arrives Monday and Tuesday, when Boise could reach 99°F, Mountain Home 97°F, and Caldwell, Nampa, and Ontario all flirting with triple digits.
The heat is expected to impact outdoor activities, roadways, and vulnerable populations. Hydrate frequently, limit outdoor exposure in the afternoon, and check on neighbors without air conditioning. The Idaho Transportation Department warns drivers to watch for heat-related pavement issues, especially on I-84 and US 20/26.
A slight cooling trend may develop over the weekend, but highs will climb again early next week. Further advisories are possible if temperatures surge above 100°F.
