Major heat wave expected to broil much of California over Fourth of July week

A beachgoer leaps over a breaking wave while heading into the water with her body board at Balboa Pier in Newport Beach earlier this month.

(Allen J. Schaben/Los Angeles Times)

A major heat wave expected across much of California over Fourth of July week is already prompting heat warnings in some areas, with triple-digit temperatures forecast and little overnight relief.

Forecasts are still developing about just how extreme and widespread the heat will be, but weather officials are confident that inland California will see several days of dangerously hot conditions, expected Tuesday through at least Friday.

Daniel Swain, a UCLA climate scientist, said the “major heatwave” also has the potential to bring hot temperatures to the coast, which he called uncommon for early July.

“Early hints at potential for some record-breaking heat and very high grass/brush fire risk,” Swain wrote on X.

A strong high-pressure system building over the central Pacific Ocean is forecast to move into the West Coast early next week, when “a hot air mass will develop over the region,” the National Weather Service wrote in its extended forecast. The weather pattern, known colloquially as a heat dome, is expected to be centered over Northern California.

An excessive heat watch has already been issued for much of inland California, from the northern Sacramento Valley to the southern Central Valley, for Tuesday through at least Friday.

“Dangerously hot conditions with high temperatures of 105 to 115” are expected, the excessive heat watch said, while overnight lows will range from the upper 60s up to around 80.

By Thursday of next week, the National Weather Service is warning of major to extreme heat risk, which officials say is “very dangerous to anyone without proper hydration or adequate cooling.”

In Death Valley, temperatures are expected to reach 120 by next weekend, according to the National Weather Service.

This weekend, temperatures across the state are expected to be average or even slightly below what is seasonally normal before the rapid warmup next week, forecasters said.

“If you’re making outdoor plans [for the Fourth of July], big and/or small, keep an eye on the forecast as it evolves through this weekend (while enjoying the seasonal temps we’re currently getting),” the weather service wrote on X.