High pressure over the Southwest will continue hot weather through at least Wednesday, according to the National Weather Service.
Heat advisories will remain in effect until at least 9 p.m. Sunday night throughout San Diego County mountain and valley areas including Cajon, Escondido, Santee, San Marcos, La Mesa and Poway with temperatures expected in the triple-digits.
Temperatures could be as high as 118 degrees and lows as high as 92 in the deserts, forecasters said.
Officials advised drinking plenty of fluids, staying in air-conditioned rooms, staying out of the sun and checking up on relatives and neighbors during extreme heat.
Children and pets should never be left inside vehicles on days that are even a little warmer than normal, as locked cars can turn into death traps in mere minutes.
High tides well over 6 feet are expected through 10 p.m. Sunday, with minor tidal overflow at low-lying beach parking lots and boardwalks.
Hot temperatures are expected to continue inland this week with slightly cooler weather by the end of the week, according to meteorologists.
“An increase of monsoonal moisture next week will bring a chance of thunderstorms mainly in the afternoons Monday through Thursday in the mountains and locally into deserts, with the greater chances on Tuesday and Wednesday,” the NWS said.
Highs in San Diego County Monday will be 75 to 80 near the coast, 84 to 89 inland, 86 to 91 in the western valleys, 96 to 101 near the foothills, 93 to 103 in the mountains and 112 to 117 in the deserts.
No hazardous marine conditions are expected through Wednesday.
City News Service contributed to this article.
