SAN FRANCISCO (KRON) — Get your jackets out; it’s going to be cold. A freeze warning has been issued in parts of the Bay Area for Wednesday night into Thursday morning, the National Weather Service (NWS) announced on Twitter.

The freeze warning applies to primarily those in Sonoma County and Napa County, according to an NWS map (below). Notable cities affected include Santa Rosa, Napa and Petaluma.

Low temperatures Wednesday night, according to KRON4 Meteorologist Lawrence Karnow

  • Santa Rosa: 30°
  • Concord: 32°
  • Napa: 34°
  • Vallejo: 38°

There will be near-to-below-freezing temperatures for most of the Bay Area, NWS said. Freezing temperatures are when it is 32° or below outside.

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Difference Between Freeze Warning and Frost Advisory

A freeze warning is more urgent than a frost advisory, according to the NWS.

A freeze warning prompts residents to take action. That is when temperatures dip below 32° for a long period of time. Those temperatures kill most types of commercial crops and residential plants.

A frost advisory urges residents to “be aware.” Residents should expect freezing temperatures that pose a threat to sensitive vegetation.