by Carlos E. Castañeda

SAN FRANCISCO (KPIX 5) – Bay Area temperatures hit the lowest levels of the season Wednesday and were likely to dip even further, with the region remaining unusually cold through next Wednesday.

A freeze warning from the National Weather Service went into effect Wednesday night at 9 p.m., and will last through Friday morning at 9 a.m.

READ MORE: Brother Joins Public Outcry Calling For Windsor Mayor Dominic Foppoli To Step Down

Wednesday morning temperatures were in the 20s in some of the Bay Area valleys, according to KPIX 5 meteorologist Lawrence Karnow.

Karnow said the a cold arctic air mass was keeping temperatures on the chilly side Wednesday with highs in the upper 40s to low 50s.

“Tonight will likely be the coldest night with many lows back into the 20s and 30s,” said Karnow. “Tomorrow will be mostly sunny but colder with highs in the 40s and low 50s.”

READ MORE: Lafayette to Consider Making Stop Sign Bird Houses Public Art Over Objections

Karnow said there is a chance of showers late on Friday with some snow possible about 2,000 feet locally.

Among the low temperatures were throughout the region Wednesday morning according the National Weather Service: 26 degrees at the Sonoma County Airport, 27 degrees at the Napa County Airport, 32 degrees in Redwood City, 34 degrees in San Jose, 43 degrees in San Francisco, 29 degrees in Concord and 42 degrees in Oakland. It was 36 degrees at Oakland International Airport.

With the freeze warning in effect, residents were advised to protect plants—especially citrus and other fragile plants—by covering them or moving small plants indoors. The same goes for exposed pipes- covering pipes with insulation or towels or blankets can prevent the cold temperatures from freezing the pipes.

Temperatures are expected to stay below average during what could be a rainy weekend, and won’t start to come back up to near normal until next Tuesday or Wednesday.

MORE NEWS: eBay Removes Listing for Art Created in California Japanese Internment Camp

(TM and © Copyright 2013 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2013 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. Bay City News contributed to this report.)