Courtesy National Weather Service
The shaded areas indicate where frost warnings were issued Sunday night into Monday morning in the region.
Southland residents awoke New Year's Eve to unusually cold weather as a frost advisory covered many areas in the region.
Cold, unstable air brought hail, rain and some snow to Southern California on Sunday, causing hazardous driving conditions and bringing delight to residents who played with the white stuff.
The National Weather Service said 2 to 3 inches of snow fell in the mountains and in the Antelope Valley foothills in northern Los Angeles county. Enough snow fell in inland areas such as Rancho Cucamonga and La Habra to allow residents to build snowmen and throw snowballs.
In San Diego, hail and rain fell during a football game at Qualcomm Stadium between the Chargers and Raiders, and lightning was reported in the mountains east of the city.
Midday snow flurry briefly slowed traffic through the Grapevine section of Interstate 5 north of Los Angeles.
The National Weather Service forecast calls for clear skies on New Year's Eve, another round of cold weather to ring in the New Year overnight and warming to the mid-60s on New Year's Day.
The dry and cool conditions should remain through New Year's Day, which is good news for Pasadena's 124th Rose Parade and the crowds that watch it pass by. Forecasters say it has only rained on the parade 10 times. The last time was in 2006, breaking a 51-year streak of no rain.