Record-breaking heat wave will hit San Diego County on Thursday

Sea surface temperatures will range from 60 to 65 degrees, providing relief from the heat.
(Gary Robbins / The San Diego Union-Tribune )

Temperatures are expected to hit or surpass 100 degrees from Rainbow to El Cajon to Potrero


A three-day heat wave that’s expected to break records across much of inland San Diego County will take hold on Thursday and peak on Friday and Saturday, as temperatures hit or surpass 100 degrees, according to the National Weather Service.

The hottest weather will occur on Friday as a dry air mass from the east moves through the region, pushing people to local beaches, where the ocean is unseasonably cool.

“We could have temperatures of 100 or more from Rainbow down to Valley Center to Escondido, Ramona, El Cajon, Alpine and Potrero,” said Mark Moede, a weather service forecaster. “And it could hit 118 at Borrego Springs and 120 at Ocotillo Wells.

“It won’t be a good time to go hiking in those areas.”

Moede said it’s highly likely that heat records will be set in such places at Ramona and El Cajon.

Over the three days, temperatures will range from the mid-to-upper 70s at local beaches to the 80s a short distance inland and 90 or above in spots like Miramar. A shallow marine layer could persist for much of the day at some beaches, particularly Oceanside.

The heat will ease a bit on Saturday, but many inland areas could reach 100.

The region won’t have to deal with high humidity; the seasonal monsoon has yet to make an appearance.

Sear surface temperatures are in the 60- to 65-degree range. They’re usually in the upper 60s to low 70s at this time of year. Recent upwelling has caused colder, deeper water to rise to the surface. Forecasters say the surf will remain small throughout the weekend.