Environment & Science

Triple-digit temps headed to parts of Southern California

File photo: Danielle Martin enjoying a cold drink as she sits in a sand hole on the beach near Melbourne.
File photo: Danielle Martin enjoying a cold drink as she sits in a sand hole on the beach near Melbourne.
Keystone/Getty Images

It's National Sunglasses Day, and you might want to put yours on to prepare for another wave of summer heat across the Southland.

A high pressure pattern is bringing warm interior temperatures to Southern California, according to Stewart Seto with the National Weather Service.

“We’re going to see this pattern where we have several days of hot weather and then a couple days of near-normal,” Seto told KPCC.

Excessive heat warnings have been issued for Santa Clarita Valley, San Gabriel Valley, San Fernando Valley and all of the mountain areas of L.A. County as temperatures and higher-than-normal humidities will push heat index values into the "danger zone" Monday, Seto said.

“Reduce the outdoor activity, don’t leave anybody in the car, don’t leave any electronics in the car and stay away from the hot parts of the afternoon,” Seto said, adding that people should avoid walking their pets on the concrete.

These tips and other heat hacks will keep you safe during days of extreme heat.

As temperatures in portions of the Inland Empire soar into three-digit numbers, the National Weather Service released an excessive heat warning that will remain in effect until Wednesday afternoon. 

The forecast predicts readings up to 103 degrees in areas like Riverside and San Bernardino — possibly 105 — NWS meteorologist Dan Gregoria told KPCC. 

“It’s not going to be quite into record territory, but it is definitely going to be hot out there,” he said.

These sizzling temperatures will be followed by a minor cool-down towards the end of the week, with a forecast for mid-90s weather, Gregoria said.

The L.A. Department of Water and Power also urges customers to conserve energy by keeping the thermostat at 78 degrees or higher, turning off unnecessary lights and only running major appliances in the early morning or late in the evening.

While the coast will stay on the cool side, Seto said to keep in mind that temperatures are measured in the shade, so in the sun, the heat can be 10 degrees to 15 degrees warmer. He also said on clear days the ultraviolet index will likely be extreme, meaning you can get burned after 15 minutes in the sun.

The beginning of summer has been hotter than usual this year, with record-breaking temperatures. Seto said average temperatures for this time of year range from 75 degrees at the coast to 86 degrees in the valleys.

This story has been updated.