Temperatures ranged from the upper 20s to mid 30s overnight. The East Bay and North Bay Valleys saw some of the most frigid temperatures. The lowest reported Thursday morning was 27 degrees in San Ramon.
Horses along Highway 12 in Sonoma County could be found breaking the layer of ice that had hardened on top of the water.
In Napa the official low Wednesday night was 25 degrees. Frost was on cars and recycling bins, but officials say that if frost gets on planes at Napa County Airport, that is bad news.
"That it destroys lift in the capacity of the wings and the other aerodynamic surfaces that operate," Jet Center Chief Flight Instructor Malcom Lenson said.
When it comes to the cold weather, Napa resident Amanda Johnson commented, "Well I have to be at work 4:30 in the morning, which means I leave at 4 a.m. so I wake up and I'm ready to go and there's ice on my car and I have to scrape it off and I'm not into that first thing in the morning."
Some good news for Amanda -- it looks like the threat of the real chill, the mid-20's they had on Wednesday night, appears to be gone just in time to bring in some rain Thursday evening.
Meteorologist Mike Nicco's forecast calls for an increase in clouds and faster breezes throughout the day. Temperatures will range from the mid to upper 50s. Steady rain moves into the North Bay after 5 p.m. and spreads south overnight.
It will be wet and windy for Friday's morning commute. Highs will be the same as Thursday Also, if you're headed to Tahoe this weekend, you might want to leave Thursday. Heavy snow is expected the next morning and will last through the weekend.