The National Weather Service has issued a frost advisory covering San Luis Obispo County effective through 9 a.m. Monday.
Forecasters expect temperatures to drop to between 29 and 32 degrees late Sunday through mid-morning Monday, according to the advisory, which also includes northern Santa Barbara County.
A dry and cold air mass is expected to allow temperatures to drop near or below freezing in some areas Sunday night and into Monday morning, and possibly again on Monday night and into Tuesday morning, according to the Weather Service.
The agency expected the coldest temperatures in San Luis Obispo, Pismo Beach, Morro Bay, Cambria, San Simeon, Santa Maria, Lompoc and the Vandenberg Air Force Base area.
The cold temperatures could kill uncovered or sensitive plants, the Weather Service warned.