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Port Costa, CA Marine Weather Forecast

Christmas Day - 56°F
Dec 25, 2025
16 to 21 mph SW
Showers And Thunderstorms
Showers and thunderstorms. Some of the storms could be severe. Cloudy. High near 56, with temperatures falling to around 53 in the afternoon. Southwest wind 16 to 21 mph, with gusts as high as 37 mph. Chance of precipitation is 100%. New rainfall amounts between a quarter and half of an inch possible.
Tonight - 50°F
Dec 25, 2025
16 to 20 mph SSW
Showers And Thunderstorms then Light Rain Likely
Showers and thunderstorms before 10pm, then rain likely. Some of the storms could be severe. Mostly cloudy, with a low around 50. South southwest wind 16 to 20 mph, with gusts as high as 36 mph. Chance of precipitation is 100%. New rainfall amounts between a quarter and half of an inch possible.
Friday - 56°F
Dec 26, 2025
9 to 16 mph S
Light Rain
Rain. Mostly cloudy. High near 56, with temperatures falling to around 52 in the afternoon. South wind 9 to 16 mph, with gusts as high as 26 mph. Chance of precipitation is 90%. New rainfall amounts between a tenth and quarter of an inch possible.
Friday Night - 45°F
Dec 26, 2025
6 to 9 mph SW
Chance Light Rain
A chance of rain. Mostly cloudy, with a low around 45. Southwest wind 6 to 9 mph. Chance of precipitation is 50%. New rainfall amounts less than a tenth of an inch possible.
Saturday - 51°F
Dec 27, 2025
7 mph N
Slight Chance Light Rain then Partly Sunny
A slight chance of rain before 10am. Partly sunny, with a high near 51. North wind around 7 mph. Chance of precipitation is 20%.
Saturday Night - 40°F
Dec 27, 2025
6 mph N
Mostly Clear
Mostly clear, with a low around 40.
Sunday - 51°F
Dec 28, 2025
7 mph NE
Mostly Sunny
Mostly sunny, with a high near 51.
Sunday Night - 37°F
Dec 28, 2025
7 mph ENE
Mostly Clear
Mostly clear, with a low around 37.
Monday - 52°F
Dec 29, 2025
6 to 9 mph ENE
Sunny
Sunny, with a high near 52.
Monday Night - 37°F
Dec 29, 2025
6 mph ENE
Mostly Clear
Mostly clear, with a low around 37.
Tuesday - 52°F
Dec 30, 2025
6 to 9 mph ENE
Mostly Sunny
Mostly sunny, with a high near 52.
Tuesday Night - 39°F
Dec 30, 2025
6 mph ENE
Partly Cloudy
Partly cloudy, with a low around 39.
Wednesday - 52°F
Dec 31, 2025
7 mph ENE
Mostly Cloudy
Mostly cloudy, with a high near 52.
Wednesday Night - 42°F
Dec 31, 2025
5 mph ENE
Mostly Cloudy then Slight Chance Light Rain
A slight chance of rain after 4am. Mostly cloudy, with a low around 42.

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