Rainfall forecast for Saturday in Southern California. Courtesy National Weather Service
Rainfall forecast for Saturday in Southern California. Courtesy National Weather Service

The biggest Pacific storm system of the rain season will spur colder and mostly cloudy conditions for Halloween trick-or-treaters in San Diego County on Friday evening.

Though there is a slight chance of light rain Friday, showers are most likely to occur in the region early Saturday morning, according to the National Weather Service.

The agency said low temperatures Friday night will be 56 to 62 degrees in coastal areas, 50 to 59 in the valleys, 38 to 48 in the mountains and 57 to 66 in the deserts.

Also later Friday, mountain and desert areas are expected to be hit with strong winds.

A wind advisory for the mountains and deserts is scheduled from 8 p.m. Friday to 5 p.m. Saturday. In issuing the wind advisory, the weather service said that west to southwest sustained winds of 25 to 35 miles per hour are possible, along with widespread gusts up to 55 mph and gusts up to 65 mph in the most wind-prone areas.

A wind advisory means that winds strong enough to make driving difficult are expected.

“Conditions will improve late Saturday afternoon,” the weather service said.

— City News Service

Chris Jennewein is founder and senior editor of Times of San Diego.