By John C. Toman. Posted December 6, 2011, 9:56 PM.

Another night of freezing temperatures is predicted for Tuesday night and Wednesday morning, along with a frost advisory.

A series of low pressure systems to the east has left clear, dry conditions ideal for radiational cooling.

Temperatures were expected to be in the 20's and lower 30's across much of the Western Riverside and Southwestern San Bernardino counties. The coldest temperatures are predicted in the higher elevations, where low in the teens are forecast for early tomorrow morning.

At 10pm Tuesday night, temperatures in Wildomar, Murrieta, Lake Elsinore and Menifee had already fallen into the 30's. Frost is not expected in Fallbrook and De Luz, and may miss some of the warmer areas around the Riverside metro.

Wednesday will be the third morning in a row for freezing temperatures in Southern California's inland valleys, but only the second with widespread frost. Winds generally kept frost from forming Tuesday.