At 2:21 a.m. on Monday, the National Weather Service released a frost advisory valid for Tuesday, Mar. 18 between 2 a.m. and 9 a.m. for North Bay Interior Valleys.

The NWS San Francisco CA adds to expect, “Temperatures as low as 32 degrees will result in frost formation.”

“Cold conditions will be hazardous to sensitive populations such as unhoused individuals. Cold conditions can lead to hypothermia with prolonged exposure,” according to the NWS. “Take steps now to protect tender plants from the cold.”

Where to find winter weather shelters in your county:

Winter weather shelters in Santa Clara County: San Jose operates the Overnight Warming Location program.

Winter weather shelters in Alameda County: List of winter shelters operated in Alameda County, from Alameda County Health Care for the Homeless.

Winter weather shelters in San Mateo County: San Mateo County residents in need of shelter should visit their local Core Service Agency in order to seek access to the Inclement Weather Program or other shelter programs.

Winter weather shelters in Contra Costa County: For information about how to connect with all emergency shelters in Contra Costa, call 211 or click on the list of shelters provided by Contra Costa Health.

Winter weather shelters in Solano County: Solano County offers a list of centers where anyone can go to keep warm during extreme weather temperatures.

Frost advisory – this is what it means

Frost advisories are issued from May to October (but can be extended if necessary) when temperatures, winds, and sky cover are favorable for frost development. This is most likely to happen when the temperature is 36 degrees or less. In some cases, the frost is severe enough to end the growing season and is then referred to as a ‘killing frost’.

According to the NWS, if a frost advisory is issued for your area, cover up sensitive plants before the sun sets so that it can help retain heat near the plants, or move the plants indoors for the night, if possible.