Temperatures in the San Diego County deserts will peak on Wednesday before slowly relenting through the weekend, according to the National Weather Service.
High pressure over the western U.S. will start moving east on Wednesday, bringing a slow cooling trend through Sunday, forecasters said. Highs in the county deserts are forecast to remain in the triple digits through Friday, then drop to the mid- to high-90s this weekend.
High temperatures today could reach 77 degrees near the coast and inland, 79 in the western valleys, 84 near the foothills, 90 in the mountains and 106 in the deserts.
An excessive heat warning that will last until 9 p.m. Thursday in the county deserts.
Nighttime lows are expected to remain in the low- to mid-70s through Thursday in the county deserts, meaning the minimal cooling at night could pose a health risk to those who don't have access to air conditioning because the body needs time to cool down from the day's heat, according to the NWS.
The combination of hot days and warm nights is expected to increase the threat of heat illness, and the NWS urged residents to drink plenty of fluids, stay out of the sun and check up on relatives and neighbors.