The National Weather Service has issued a frost advisory for much of the Bay Area, including Berkeley, warning of hazardous temperatures for unhoused residents. The advisory goes into effect today at midnight and lasts through Tuesday morning. 

In Berkeley, temperatures are expected to drop to around 36 degrees tonight and 38 Tuesday night due to a phenomenon known as radiational cooling, said NWS meteorologist Jeff Lorber. When skies are clear and winds are calm, there’s “better radiation from the surface, which allows warmer air or heat that’s accumulated during the day to escape into the atmosphere,” Lorber explained. 

The NWS recommends people exercise its “Four Ps” of cold weather protection.

  • People: Wear layers, limit time outdoors, check heaters in advance.
  • Plants: Cover or bring sensitive plants indoors.
  • Pets: Bring pets indoors at night and provide them with plenty of warmth.
  • Pipes: Wrap or cover exposed outdoor pipes to prevent freezing. 

Expect wind gusts of up to 25 mph today and 20 mph Tuesday. 

It’ll start to warm back up on Thursday, but don’t put away your jackets quite yet: Light rain is forecast to arrive Thursday night and last through Sunday, bringing around half an inch of rain to Berkeley over the four days. 

The rain this week, coming from the Northern Pacific Ocean, is not expected to be anywhere as destructive as the parade of atmospheric river storms between late December and mid-January that triggered mudslides in Berkeley and brought down more than 20 trees on city land, according to parks director Scott Ferris. 

Berkeley’s soils are still fairly saturated from the winter storms, Lorber said, but flooding is not currently a major concern with this weather system, as recent dry weather has allowed some of the moisture in the ground to evaporate.

Iris Kwok covers the environment for Berkeleyside through a partnership with Report for America. A former music journalist, her work has appeared in the San Francisco Chronicle, KQED, San Francisco Examiner...