The National Weather Service issued warnings as Southern California prepared for a weeklong heat wave beginning Tuesday and hazardous surf from Tropical Storms Elida and Fausto along the coast. The advisories covered inland areas including the Inland Empire inland Orange County, San Diego County valleys, deserts and mountains. Last updated: July 20, 2026.
The dual threat mattered because the combination of extreme inland heat, elevated humidity and large offshore swells increased risks to public health, coastal recreation and wildfire potential. Officials warned residents to limit outdoor exposure during peak heat, prepare for dangerous swimming conditions and remain alert for critical fire weather where weak-to-moderate sundowner winds could accelerate flames.
Heat wave forecast and temperature projections
Forecasters projected a seven-day event driven by a strong ridge of high pressure centered over the interior West, producing widespread warming and drying. By midweek, specific locations were forecast to reach high values: Lancaster around 105 degrees, Canoga Park near 103, and Santa Clarita about 98 degrees, with downtown Los Angeles and coastal cities substantially cooler but still warm. Interior valleys in the Inland Empire and San Diego County were expected to exceed 100 degrees, and desert areas could surpass 110 degrees.
The heat wave carried a concurrent critical fire weather threat beginning Tuesday and extending into the following week for interior areas. Weak-to-moderate sundowner winds in southwestern Santa Barbara County were forecast, conditions that historically can lead to rapid fire spread if ignitions occur. Public health messaging emphasized hydration, shaded breaks for outdoor workers, and awareness of heat illness symptoms.
Hazardous surf from Elida and possible Fausto swell
Tropical Storm Elida tracking northward from off southern Mexico, was expected to remain well offshore but to generate elevated swells and strong rip currents for south-facing beaches. Observed and forecast surf heights ranged from 4 to 8 feet on affected beaches, with Orange County south-facing breaks already seeing 4 to 6 foot waves and occasional 6 to 8 foot sets. Forecasters cautioned swimmers and coastal recreationists that hazardous swimming conditions could persist through at least Tuesday.
A second tropical system, Fausto held the potential to produce an additional pulse of elevated swell later in the week and into the weekend, prolonging hazardous surf and rip current threats. Beachgoers were advised to heed local warnings and lifeguard instructions and to assume strong currents where surf was elevated.
Marine heat wave, humidity and implications
Sea surface temperatures off Southern California remained among the warmest for this time of year, part of an ongoing marine heat wave that increased coastal humidity and reduced overnight relief. Those warm waters were not attributed to El Niño at this time, with forecasters noting the marine anomalies rivaled past strong warm events. Elevated humidity combined with high daytime temperatures raised overnight risks for heat-related illness.
Authorities continued to monitor the overlapping hazards — heat, humidity, hazardous surf and heightened fire weather — and urged residents to stay informed as conditions evolved. The situation remained subject to updates as the tropical systems and high-pressure ridge progressed.
