A layer of frost covered cars, plants and roadways Tuesday as temperatures across the county dropped into freezing territory overnight.
Overnight temperatures dipped into the low 30s amid a frost advisory in effect until 9 a.m. Tuesday due to the unseasonably chilly conditions, the National Weather Service said.
Temperatures will rise to the low 60 degree-mark along the coast and in the inland valleys and deserts while remaining in the low 40s for the mountains, NBC 7 Meteorologist Sheena Parveen said.
Another chilly night is expected Tuesday and a frost advisory will again go into effect at 10 p.m. for the overnight hours.
The NWS said during the advisory period, residents should shield sensitive outdoor plants and bring pets inside or provide shelter.
On top of cold conditions, San Diego is bracing for its next bout of rain expected to touch down late Wednesday afternoon.
The storm system will first increase winds before dumping anywhere from a half-inch of rain at the coast to an inch-and-a-half of rain inland.
Mountains could see more snow at elevations above 4,000 feet and could drop to elevations as low as 2,000 feet during frigid overnight conditions on Thursday into Friday.
Up to 6 inches of snow is possible at the highest elevations.