A dry, cold air mass will bring sub-freezing temperatures to parts of Southern California during overnight and early-morning hours this week.
The coldest areas are expected to be the Antelope Valley and, to the north, the interior valleys of San Luis Obispo and Santa Barbara counties.
A frost advisory issued by the National Weather Service will be in effect in the Antelope Valley from 3 a.m. to 9 a.m. today, and a freeze watch will be in force from late tonight through Thursday morning.
Today in Santa Monica the forecast is for a high of 69 and a low of 52 tonight. On Thursday expect a high of 73 with another low of 52 tomorrow night.
An NWS statement said temperatures of between 32 and 35 degrees Fahrenheit are expected in the Antelope Valley this morning until the frost advisory expires, and temperatures of between 27 and 32 degrees are expected Thursday morning.
In such temperatures, “sensitive plants and crops can be damaged and unsheltered animals can be harmed,” the statement said, adding that animals should be brought indoors or placed in a barn, and measures need to be taken to protect sensitive plants.
Highs today are expected to be in the upper 50s in the Antelope Valley and the upper 60s in much of the rest of the region.
The NWS forecast sunny skies today and highs of 56 on Mount Wilson; 58 in Palmdale; 59 in Lancaster; 65 in Saugus; 67 in San Clemente and Mission Viejo; 68 in Avalon, Burbank, Irvine and Newport Beach; 69 at LAX and in Pasadena, Yorba Linda, Fullerton, Anaheim and Laguna Beach; 70 in Long Beach and San Gabriel; and 71 in downtown L.A. and Woodland.
Temperatures will rise a few degrees Thursday — four degrees in both downtown L.A. and Woodland Hills — than another three or four degrees through Saturday before falling back Sunday. Monday’s temperatures will be similar to today’s.