California heat wave triggers closures as 111-degree temps slam SoCal

San Diego, California – Southern California is in the grip of a dangerous heat wave this week, with inland areas facing triple-digit temperatures and some popular recreational spots shuttered for public safety. The National Weather Service has issued a heat advisory through 8 p.m. Wednesday for San Diego County’s inland valleys and mountain communities, where temperatures are expected to climb into the upper 90s—potentially breaking seasonal records.

The advisory applies to cities including El Cajon, San Marcos, Poway, Escondido, Santee, Pine Valley, and Julian. In the Inland Empire, forecasts call for highs of up to 102 degrees, while the Coachella Valley could reach a blistering 111. Meanwhile, coastal areas are enjoying relatively moderate highs in the mid-70s, with temperatures rising to the high 80s further inland.

The elevated temperatures—running 10 to 15 degrees above normal for mid-June—have triggered closures of popular hiking destinations like Three Sisters Falls and Cedar Creek Falls. The U.S. Forest Service says the decision is meant to prevent heat-related medical emergencies in remote areas where emergency response is difficult.

Meteorologists warn that the heat carries serious health risks, particularly for vulnerable groups such as older adults, young children, and people with chronic illnesses. Prolonged exposure can quickly lead to heat exhaustion or heat stroke, even in those who are otherwise healthy. Officials are urging residents to stay hydrated, limit outdoor activity during peak heat hours, and check on neighbors and family members who may need help staying cool.

Animal safety is also a concern. Authorities are reminding pet owners never to leave animals in vehicles or unventilated garages and to ensure pets have access to shade and fresh water at all times.

This intense stretch of summer-like weather arrives just days before the official start of summer on Friday. But it won’t last. A cooldown is expected to begin Thursday, bringing temperatures back down to more seasonal—and in some cases, below-average—levels by the weekend. Some of the same areas now sweltering under near-triple-digit heat could be as much as 15 degrees cooler by Sunday.

Still, the risk isn’t limited to high temperatures alone. Dry conditions and gusty winds are creating fire weather concerns in parts of Southern California, particularly the Antelope Valley, the Interstate 5 corridor, and southern Santa Barbara County.

In the meantime, public health officials urge residents not to wait until they feel thirsty to drink water, to avoid sugary drinks and alcohol, and to watch closely for signs of heat stress.