Historic high hits southern Idaho
BOISE, Idaho — Saturday, May 31, 2025, will go down in the books as Idaho’s first triple-digit day of the year, as temperatures soared to 100°F (37.8°C) in the Boise region, breaking previous records for this date. This spike marked the earliest 100-degree reading of 2025, ushering in what may be a hot and intense summer ahead.
The heat advisory issued for south central and southwest Idaho, as well as parts of northeast and southeast Oregon, remained in effect until 7:00 p.m. MDT (6:00 p.m. PDT). According to the National Weather Service, residents in areas along the I-84 corridor experienced temperatures up to 97°F (36.1°C), and the brief but intense heatwave pushed urban zones into the triple digits, especially across the Treasure Valley.
Cooler shift beginning Sunday
The good news for residents and visitors is that this intense heat won’t last much longer. Beginning Sunday, June 1, the region will enjoy a noticeable cooldown. Highs in the 80s°F (26–30°C) are expected Sunday, with a further drop into the 70s°F (21–26°C) forecast for the start of the work week across southern Idaho, including Boise, Meridian, and Nampa.
This brief temperature dip will offer a much-needed break for outdoor workers, families, and local travelers—especially in communities like McCall, where tourism activity is ramping up with the warmer season.
Gradual warm-up returns midweek
As the week progresses, however, a slow and steady warming trend will return to southern Idaho. By next weekend, Treasure Valley will likely climb back into the 90s°F (32–35°C), while Magic Valley, including cities like Twin Falls, can expect upper 80s°F (31°C) by Saturday, June 7.
Heat safety still critical
The heat advisory emphasized the need to stay hydrated, avoid prolonged sun exposure, and check on vulnerable individuals. Residents were reminded to never leave children or pets unattended in vehicles, even for short periods.
As temperatures continue to fluctuate, the Occupational Safety and Health Administration recommends frequent rest breaks in shaded or air-conditioned spaces and light, loose-fitting clothing for anyone working outdoors. With summer just beginning, knowing the signs of heat-related illness remains essential across Idaho’s diverse landscape.
Stay tuned for daily updates as June kicks off with a dramatic temperature rollercoaster in the Gem State.
