San Diego County Braces for Prolonged Heat Wave with 90-Degree Temps

San Diego County is experiencing a prolonged heat wave, with temperatures in the 90s for inland and mountain areas and in the 100s for the deserts. The heat wave, caused by a persistent high-pressure system, is expected to continue through the week and into the weekend, posing potentially dangerous conditions. An excessive heat warning has been extended until 8 p.m. Friday for the deserts, where temperatures could reach 115 to 121 degrees. The mountains and valleys will have less severe impacts, while the coast will be about 15 degrees cooler due to a marine layer and low clouds. The peak of the heat is expected this weekend, with high temperatures near 115 degrees continuing through the week. It is advised to stay hydrated, stay in air-conditioned rooms, avoid the sun, and check on vulnerable individuals.