High heat and rare tropical humidity over Southern California
This weekend in Los Angeles, residents should brace for continued hot conditions blended with unexpected tropical humidity, creating a rare and uncomfortable mix for late May. While Friday’s peak heat was slightly below forecasted extremes, downtown Los Angeles still climbed to 96°F (35.5°C), breaking a 1972 record by one degree.
Woodland Hills and Chatsworth hit triple digits, and similar temperatures are expected to persist, especially across valley regions. According to the National Weather Service, Saturday will bring highs ranging from the mid-70s (24°C) along the coast to the low 90s (32°C) inland, with heat advisories slowly expiring but still in effect for much of Southern California.
Moisture from weakening Tropical Storm Alvin
Even as Tropical Storm Alvin weakens off the Baja California coastline, its lingering moisture is set to stream into Los Angeles County, bringing a chance of light showers and isolated thunderstorms. While Ventura County may also experience sporadic rain, forecasters emphasize that not all areas will see precipitation. The added humidity will make already high temperatures feel more oppressive, especially in urban zones.
Heat continues to intensify across valleys and deserts
Areas such as the San Fernando Valley, Santa Clarita Valley, and portions of the Central Coast remain under elevated heat risk. Temperatures here could exceed 100°F (37.7°C), with extreme heat advisories in effect through the weekend. In parts of Central California—including Merced, Fresno, and the San Joaquin Valley—the National Weather Service in Monterey projects highs reaching 106°F (41.1°C).
The Yosemite Valley, Sierra foothills, and nearby mountain zones are also forecast to endure intense heat, while Death Valley remains under an extreme heat warning through Saturday night, with temperatures over 115°F (46.1°C).
Fire weather risk grows in the Sierra Nevada
The National Weather Service in Reno has declared a fire weather watch from Saturday morning through Sunday evening for areas in and around the Sierra Nevada. The combination of gusty winds, low humidity, and dry lightning introduces a significant fire danger. Forecasters mention a 10% to 15% chance of isolated dry thunderstorms—events capable of igniting wildfires amid unstable atmospheric conditions.
Heat-related health risks in Los Angeles County
The Los Angeles County Public Health Department continues to emphasize the serious health threats posed by this heatwave, particularly for older adults, young children, and those with chronic conditions. Symptoms of heat-related illness may include dizziness, vomiting, confusion, and hot, red or damp skin. In case of these signs, seek emergency help and move to a cool environment.
For those without access to air conditioning, cooling centers, community pools, and splash pads remain open across the county. Locations are listed on the Ready L.A. County website under Find Relief From the Heat.
The weekend outlook: steamy, stormy, and potentially record-breaking
As temperatures flirt with record levels across the Western United States, the presence of tropical air combined with blazing sunshine will create an unusually humid heat profile for Los Angeles and surrounding regions through Sunday. While relief is expected gradually, the combination of heat, humidity, and possible thunderstorms makes for a volatile and uncomfortable weather pattern in Southern California this weekend.
