San Diego weather is turning hotter and more humid as monsoon moisture moves into San Diego County. On Thursday, temperatures across the county are expected to run up to five degrees above average, with isolated showers and thunderstorms possible.
The deserts remain under an Extreme Heat Warning through Saturday, with highs of 109 to 115 degrees possible. Mountain areas are under a Heat Advisory, and overnight lows in the mountains and deserts are expected to stay unusually warm, leaving little relief after sunset.
San Diego County deserts
For residents in the San Diego County Deserts, Thursday’s high could reach around 110 degrees, while coastal areas are expected to stay in the upper 70s and low 80s. The forecast also calls for a mix of sunshine, marine layer clouds near the coast, and increasing afternoon cloud buildup over the mountains and deserts.
That combination means the county is not dealing with one uniform pattern. The coast stays much cooler than the interior, while the mountains and deserts face both stronger heat and the chance of developing storms in the same stretch of weather.
Sunday and Monday
A stronger chance of showers and thunderstorms is expected Sunday and Monday. The shift comes as the region stays in a more tropical-feeling pattern through at least mid-August, extending the period of humid air over the county.
Residents are urged to stay hydrated, avoid outdoor activity during peak heat, never leave children or pets in vehicles, check vehicles for fire hazards, trim vegetation around homes, and keep emergency supplies ready. For people in the deserts, the warning through Saturday is the most immediate concern; for everyone else, the practical move is to treat Thursday and the weekend as a stretch of changing conditions rather than a single hot day.
