SAN DIEGO, California — A significant heat wave is taking shape across San Diego County this week, with inland areas under a heat advisory and desert regions bracing for extreme heat. This marks the first major hot spell of the summer season.
Monday kicked off with a gradual warmup, and by Tuesday, temperatures are expected to rise further, culminating in dangerous highs on Wednesday and Thursday.
Heat advisory for inland San Diego County
The National Weather Service (NWS) has issued a heat advisory effective from 10 a.m. Wednesday through 8 p.m. Thursday for inland communities across San Diego County.
Areas such as La Mesa, Escondido, El Cajon, San Marcos, Santee, and Poway are forecast to experience daytime highs between 97°F and 101°F (36°C–38°C). The valley zones, especially those east of Interstate 15, will see the most intense heat, with moderate to high heat risk anticipated.
The NWS San Diego emphasizes that these elevated temperatures pose a risk for heat-related illnesses, particularly for individuals spending extended periods outdoors or without access to air conditioning.
Extreme heat warning for San Diego deserts
Simultaneously, from 10 a.m. Wednesday until 8 p.m. Thursday, the desert regions of San Diego County—including areas like Borrego Springs—will be under an extreme heat warning.
Temperatures in the deserts are expected to climb between 115°F and 120°F (46°C–49°C), reaching critical levels that significantly increase the chance of heat exhaustion or heat stroke. The NWS warns that the heat risk will be severe, especially for heat-sensitive groups or those lacking adequate hydration and cooling systems.
In addition to the record-breaking temperatures, humidity levels are expected to rise slightly, adding moisture to the air and causing the “feels-like” temperature to spike even higher.
Cooler air by the weekend
Although the midweek stretch will bring the most intense heat, a slight cooling trend is forecast by Saturday and Sunday, with inland temperatures dipping to around 85°F (29°C).
Meanwhile, coastal areas of San Diego, including neighborhoods near the Pacific, will remain significantly cooler throughout the week, peaking at the upper 70s to low 80s (25°C–28°C) during the warmest days.
The NWS continues to urge caution during this heat event, particularly for those in eastern inland valleys and the desert corridor, where daytime highs and overnight lows will offer little relief.
