Boise, ID – Unseasonably warm temperatures are expected across southern Idaho on Wednesday, with highs near 80°F in several cities, marking the region’s first taste of summer-like conditions in 2025.
According to the National Weather Service in Boise, a ridge of high pressure will drive temperatures to near-record highs from 8 a.m. to 9 p.m. MDT on March 26. Boise, Mountain Home, and Nampa are forecast to reach between 77°F and 81°F, while nearby areas like Caldwell and Ontario may also hit the upper 70s.
The unusually warm air will significantly boost snowmelt in central and northern Idaho. Locations such as McCall and Stanley will remain cooler, in the upper 50s, but the increase in runoff could elevate river levels statewide. The NWS warns that rapid warming may impact backcountry travel and increase avalanche risk in mountain zones.
Drivers and outdoor workers should prepare for higher daytime heat, especially in low-elevation valleys. Residents are advised to monitor changing river flows and avoid flooded roadways.
This warm spell is expected to break by Thursday as temperatures drop back to seasonal norms. The NWS forecasts Boise to fall to 61°F by Friday, signaling a return to more typical March conditions.
