A cold blast is forecast to hit the North Coast tonight, bringing below-freezing overnight temperatures through the weekend.
The sharp dip is expected to fill shelters and could threaten outdoor plants.
"Overall, this may be some of the coldest weather we've had this winter," senior AccuWeather meteorologist Bob Smerbeck said Wednesday. "Anyone with susceptible plants better have a game plan beginning Thursday night."
Daytime highs are expected to be in the upper 40s with cloudy skies and rain possible Saturday night, Smerbeck said.
The chilly conditions will continue through the beginning of next week, he said.
It's not the first cold snap this winter. Temperatures in Sonoma County dropped to 26 degrees Dec. 19. But Smerbeck said it will be the longest period of freezing weather so far.
In Santa Rosa, temperatures will drop to 29 degrees overnight tonight, 32 on Friday and Saturday and 30 on Sunday.
Ukiah and the Napa Valley will have slightly lower temperatures.
It's all part of a cold front coming down from western Canada and sweeping across the country.
Smerbeck said the normal high this time of the year in Santa Rosa is 58 and the normal low is 39.