This year’s Ocean Beach Christmas tree was set up and decorated on Dec. 1 and Dec. 2. Photo by Chris Stone

The first day of winter in San Diego County will be “fair and unseasonably warm” with highs reaching the low 80s in many areas, the National Weather Service said.

Highs on Monday will be 71 to 76 near the coast, 77 to 82 inland, 79 to 84 in the valleys, 66 to 74 in the mountains and around 78 in the deserts.

On Tuesday a Pacific trough will move inland, carrying cooler and more humid, marine air inland, along with gusty westerly winds over the mountains and deserts, the weather service said.

“Another, potentially stronger Santa Ana will bring more dry, gusty offshore winds Wednesday into Thursday,” forecasters said. “Look for more high clouds and less wind late Thursday and Friday as a weak upper-level trough moves by.”

A more dynamic weather system early next week could bring the county some precipitation.

— From Staff and Wire Reports