It hardly ever freezes in Port Costa
Port Costa has warm winters and pleasant summers, with very little rain. A typical July afternoon reaches 81°, a January night drops to 40°, and snow is almost unheard of. In November, a normal day reaches 65° and a normal night drops to 45°.
Getting the latest forecast from the National Weather Service…
What stands out about Port Costa’s weather
Read from 30 years of NOAA records. Each one opens the full story on the Climate page.
Where today sits in Port Costa’s year
Typical highs and lows month by month, from 30 years of NOAA records.
Weather talk
Road reports, first frosts and storm memories from neighbors in Port Costa.
Your answer becomes a post in Town Square.
Forecast, conditions and alerts: National Weather Service. Climate: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000. Temperatures and rainfall come from NOAA’s gridded normals for Port Costa itself (about a 3-mile square). Snow, frost dates and day counts: the NOAA station at Napa State Hospital, CA (17 mi, snow) and Vallejo, CA (4 mi, frost, heat and degree days). Sunrise and sunset are calculated from the town’s position. Normals are 30-year averages, not a forecast.