Extreme Heat Wave Threatens San Diego County With Dangerous Swells

A severe heat wave will spread across San Diego County through Friday, pushing inland temperatures up to 115 degrees and triggering high surf conditions along coastal areas, according to forecasters from the National Weather Service on August 23, 2026.

A strong high-pressure ridge over the Southwest is driving daytime temperatures between 8 and 12 degrees above normal across the region. While coastal areas will see highs near 88 degrees, inland valleys will reach up to 107 degrees, and lower desert regions such as Borrego Springs are forecast to hit 115 degrees.

An Extreme Heat Watch takes effect from Tuesday morning through Friday evening for coastal zones, valleys, and mountains. The heat watch follows an earlier Heat Advisory for inland communities, while desert areas remain under an Extreme Heat Warning through Friday night. Elevated overnight lows in the mid-70s are expected to offer little relief, increasing overall health risks.

Monsoonal moisture returning to Southern California will bring a minor chance of isolated afternoon showers and thunderstorms over the mountains and deserts, which could produce gusty winds and lightning. Meanwhile, a 4- to 5-foot southerly ocean swell will arrive by Wednesday and Thursday, creating breaking waves of up to 8 feet, strong rip currents, and localized coastal flooding along south-facing beaches.

Local health officials urged residents to limit strenuous outdoor activity during peak daylight hours, maintain adequate hydration, and check on vulnerable individuals. Public facilities, including community centers and libraries, are designated as cool zones to assist residents without access to indoor air conditioning.