Southern California's Most Dangerous October Heat Wave in Decades Has Millions on Alert

PASADENA, CALIFORNIA - OCTOBER 05: An unofficial outdoor thermometer reads 96 degrees amid a heat wave on October 05, 2026 in Pasadena, California. An extreme heat warning is in place for much of Southern California until late Thursday with high temperatures reaching above 90 degrees F along the coast, and with some inland high temperatures topping 100 degrees. (Credit: Photo by Mario Tama/Getty Images)

The Briefing:

• More than 34 million Californians remain under active heat alerts as of this week, with Extreme Heat Warnings covering eight Southern California counties — including Los Angeles, Ventura, Santa Barbara, Orange, San Bernardino, Riverside, and San Diego — through 8 p.m. Thursday, October 8.
• Inland temperatures have crossed 100°F / 38°C across the Southland, with coastal areas reaching the low-to-mid 90s — readings more typical of August than early fall — making this one of the longest and most intense October heat events in regional memory.
• A gradual cooling trend is expected to begin Thursday, with temperatures not returning to near-normal fall levels until the following weekend — meaning residents should treat the next 48 to 72 hours as the most critical window of this event.