Boise, Idaho – Temperatures across the lower Treasure Valley will surge into the triple digits beginning Sunday afternoon, with a Heat Advisory in effect from 12 p.m. Sunday until 9 p.m. Monday. Residents from Boise and Meridian to Caldwell and Ontario can expect highs reaching 100°F or higher, raising risks for heat-related illnesses and stressing local infrastructure.
According to the National Weather Service in Boise, the Heat Advisory covers Ada, Canyon, Payette, and Malheur counties, as well as surrounding areas. Daytime highs on Sunday and Monday will run 5 to 10 degrees above July normals, topping out at 101°F in Meridian, 102°F in Ontario, and 100°F in Mountain Home. The advisory urges people to avoid outdoor activity during the hottest parts of the day and check on vulnerable neighbors, children, and pets.
Local agencies recommend staying hydrated, limiting outdoor chores to early morning or late evening, and using air conditioning where possible. Drivers should never leave children or pets in parked vehicles. Schools, outdoor workers, and utility crews are urged to take extra precautions as heat can impact power grids and lead to possible outages.
This heat wave follows a cooler-than-average start to July, but resembles last summer’s mid-July surge. Relief is expected by midweek, with highs dropping back into the 80s and low 90s by Wednesday. Additional advisories may be issued if conditions persist.
Warnings remain in effect through 9 p.m. Monday. Monitor local alerts for the latest updates.
Five Day Forecast for Boise & Treasure Valley:
- Sunday, July 13: Morning low 69°F, high 100°F, sunny and very hot
- Monday, July 14: Morning low 71°F, high 100°F, extreme heat continues
- Tuesday, July 15: Morning low 67°F, high 95°F, hot but slightly cooler
- Wednesday, July 16: Morning low 64°F, high 90°F, partly cloudy, breezy
- Thursday, July 17: Morning low 62°F, high 96°F, warming again, sunny
