National Weather Service advisories affected much of Southern California as authorities prepared for an intense heat wave beginning Wednesday and extending through the following Monday, centered on Los Angeles and surrounding counties. Last update: July 22, 2026. The advisory covered Los Angeles, San Diego, Orange, Riverside, San Bernardino, Ventura and Santa Barbara counties and warned of prolonged high temperatures and elevated humidity.
Why the heat wave mattered and its expected duration
The heat wave was significant because meteorologists described both peak daytime temperatures and minimal overnight cooling, increasing the risk of heat illness, strain on power systems and higher fire potential. Forecasts indicated the event would persist into the last week of July with a 60% to 80% chance of above-normal temperatures between July 27 and August 2, and an 80% probability noted earlier that the heat would be prolonged and dangerous through the weekend.
Forecasted highs, overnight lows and area-specific expectations
Forecasters projected specific highs across the region, with inland and valley communities reaching the highest numbers. Temperatures were expected as high as 109°F in Paso Robles108°F in Lancaster and lows remaining elevated, with the L.A. Basin overnight lows near 70°F and valley lows in the low to mid-70s beginning Thursday. Additional forecasts included 106°F in Canoga Park, 105°F in Van Nuys, 103°F in Santa Clarita, 100°F in North Hollywood and 92°F in downtown Los Angeles, with coastal areas such as Long Beach remaining cooler around 87°F. Interior valleys of San Diego County and the Inland Empire were predicted to exceed 100°F while the deserts could surpass 110°F. Model guidance showed little nighttime relief, increasing cumulative heat stress on vulnerable populations and infrastructure.
Fire danger, tropical influences and hazardous coastal conditions
The combination of extreme heat and instability raised an enhanced risk for large fires away from the coast, with officials warning of fast-moving, plume-dominated fires that can spread rapidly even without strong winds. Sundowner-type winds were highlighted as a particular concern for southwestern Santa Barbara County, where expected offshore winds could accelerate any ignition. In addition to the fire threat, coastal hazards were forecast as strong rip currents and high surf affected beaches; a high-surf advisory was in place for areas including Catalina and the Malibu coast until at least 11 p.m. Tuesday. Tropical systems south of California, including Tropical Storm Fausto and the remnants of Tropical Storm Elida, were cited as drivers of increased swell and dangerous surf along the shorelines.
Who was at risk and public-safety guidance
Populations identified as most at risk included outdoor workers, residents without air conditioning, people over 65, young children and others with medical vulnerabilities. Public guidance emphasized limiting outdoor activity to early mornings, seeking air-conditioned shelter in the afternoon and evening, staying hydrated and checking on vulnerable neighbors. Authorities reiterated that children and pets should never be left unattended in vehicles. The prolonged nature of the event prompted officials to advise preparations for extended hot conditions and to monitor local cooling centers and community resources as needed.
The situation remained under active monitoring by meteorological and emergency-management authorities, and residents across the advisory area were advised to follow local updates for any elevation of warnings or changes in expected timing and impacts. Last update: July 22, 2026.
