A frost advisory is in effect from midnight until 8:00 a.m. tomorrow morning for Riverside County and its surrounding areas, according to a National Weather Service report.
Temperatures are supposed to drop down to the 20s and 30s in valley areas in Riverside and San Diego Counties.
Drivers should exercise caution as roadways and underpasses may become icy due to the relative humidity, the report said.
Sensitive outdoor plants could be damaged or killed by the frost if left uncovered, according to the report.








