San Diego, CA – A surge of early-season heat is set to grip Southern California within days, pushing inland temperatures toward 105°F and raising heat illness risks for millions across San Diego, Orange, and Riverside counties starting Monday morning.
According to the National Weather Service in San Diego, an Extreme Heat Watch begins at 10 a.m. Monday and continues until 8 p.m. Friday, covering coastal and inland communities from San Diego County through the Inland Empire. Temperatures are expected to run 20 to 30 degrees above normal, with coastal areas climbing into the mid to upper 80s while inland valleys approach 94°F to potentially 105°F during peak afternoon hours.
Cities including San Diego, Escondido, El Cajon, San Marcos, and Vista could see rapid warming by midday Monday, while hotter inland areas such as Riverside, Corona, Ontario, and Rancho Cucamonga face the greatest heat intensity. High energy demand is likely as air conditioners run longer, and transportation agencies including Caltrans warn pavement temperatures along major corridors like Interstate 5, I-15, and State Route 78 could exceed 130°F in direct sun.
Health officials urge residents to drink water frequently, stay inside air-conditioned buildings during the afternoon, and check on older adults or neighbors without cooling. Never leave pets or children in vehicles; interior temperatures can turn deadly within minutes.
The heat builds Monday and is expected to hold through the end of the workweek, with additional advisories possible if temperatures trend higher across inland Southern California.
Five Day Forecast for San Diego, California
Saturday: High 75°F – Increasing clouds
Sunday: High 76°F – Patchy fog early, then mostly sunny
Monday: High 84°F – Sunny
Tuesday: High 88°F – Sunny
Wednesday: High 88°F – Sunny
