The National Weather Service has posted 33 active heat alerts across ten states and Puerto Rico as of Tuesday, with forecast highs reaching 105 to 110 degrees in parts of Northern California and triple-digit readings extending from the Southwest into the Texas Panhandle.
The advisories stretch from Arizona, California, Colorado, Kansas, Nevada, New Mexico, Oregon, Texas and Utah to Puerto Rico, according to the National Weather Service. The heaviest concentration of alerts is in California, where dozens of zones are under advisory, including Trinity County, where the Weather Service is forecasting 105 to 110 degrees and warning of moderate to major heat risk from 11 a.m. Tuesday through 11 p.m. PDT Thursday. Interior Del Norte County, Lake County and the interior Mendocino County zones face highs up to 105 through Tuesday night.
The advisory zone runs south through California’s Central Valley, covering the Sacramento Metro area, San Joaquin County and the Stockton Metro area, Modesto Metro and surrounding Stanislaus County communities, as well as the interior valleys and mountains of San Luis Obispo and Santa Barbara counties. In Texas, the alerts extend into the Panhandle, covering Briscoe, Hall, Childress, Motley and Cottle counties.
The National Weather Service is warning that hot temperatures, and in some zones high humidity, may cause heat illnesses. The agency’s standard guidance for residents under advisory: drink plenty of fluids, stay in an air-conditioned space, stay out of direct sun, and check on relatives and neighbors, particularly those who are elderly or without reliable air conditioning.
The scope of Tuesday’s alerts underscores how widespread this heat event is — spanning the Pacific Coast, the Great Basin, the Rockies, the southern Plains and the Caribbean simultaneously. Some advisories are set to expire Tuesday night, but the Trinity County alert and others in Northern California’s foothill and valley zones remain in effect into Thursday, meaning residents in those areas face at least three consecutive days of elevated heat risk before conditions ease.
Residents in the affected regions, including those near Sacramento weather and Fresno weather, should check local forecasts for the specific timing of peak heat in their area, since advisory windows vary by county and elevation across this multi-state event.