National Weather Service Forecast for: Fullerton CA
Issued by: National Weather Service San Diego, CA
Updated: 8:40 pm PST Dec 22, 2025
 
Tonight

Tonight: Patchy fog. Otherwise, cloudy, with a low around 55. Calm wind.
Patchy Fog

 Tuesday

Tuesday: Showers likely, mainly after 4pm. Cloudy, with a high near 66. Southeast wind 5 to 10 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Slight Chance
Showers then
Showers
Likely
 Tuesday
Night
Tuesday Night: Showers. The rain could be heavy at times. Low around 59. East wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 90%. New precipitation amounts between 1 and 2 inches possible.
Heavy Rain

 Wednesday

Wednesday: Showers, with thunderstorms also possible after 10am. Some of the storms could produce heavy rainfall. High near 65. South wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.
Heavy Rain

 Wednesday
Night
Wednesday Night: Showers and possibly a thunderstorm. Low around 56. Calm wind becoming east around 5 mph after midnight. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.
Showers

 Christmas
Day
Christmas Day: Showers. High near 65. Chance of precipitation is 90%.
Showers

 Thursday
Night
Thursday Night: Showers. The rain could be heavy at times. Low around 54. Chance of precipitation is 90%.
Heavy Rain

 Friday

Friday: Showers, mainly before 4pm. Mostly cloudy, with a high near 62.
Showers

 Friday
Night
Friday Night: A chance of showers. The rain could be heavy at times. Mostly cloudy, with a low around 46.
Heavy Rain
Lo 55 °F Hi 66 °F Lo 59 °F Hi 65 °F Lo 56 °F Hi 65 °F Lo 54 °F Hi 62 °F Lo 46 °F

Flood Watch
Wind Advisory
 

Tonight
 
 Patchy fog. Otherwise, cloudy, with a low around 55. Calm wind.
Tuesday
 
 Showers likely, mainly after 4pm. Cloudy, with a high near 66. Southeast wind 5 to 10 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Tuesday Night
 
 Showers. The rain could be heavy at times. Low around 59. East wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 90%. New precipitation amounts between 1 and 2 inches possible.
Wednesday
 
 Showers, with thunderstorms also possible after 10am. Some of the storms could produce heavy rainfall. High near 65. South wind 10 to 15 mph, with gusts as high as 25 mph. Chance of precipitation is 100%. New rainfall amounts between 1 and 2 inches possible.
Wednesday Night
 
 Showers and possibly a thunderstorm. Low around 56. Calm wind becoming east around 5 mph after midnight. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.
Christmas Day
 
 Showers. High near 65. Chance of precipitation is 90%.
Thursday Night
 
 Showers. The rain could be heavy at times. Low around 54. Chance of precipitation is 90%.
Friday
 
 Showers, mainly before 4pm. Mostly cloudy, with a high near 62.
Friday Night
 
 A chance of showers. The rain could be heavy at times. Mostly cloudy, with a low around 46.
Saturday
 
 A slight chance of showers. Mostly sunny, with a high near 62.
Saturday Night
 
 Partly cloudy, with a low around 45.
Sunday
 
 Sunny, with a high near 65.
Sunday Night
 
 Mostly clear, with a low around 47.
Monday
 
 A slight chance of showers. Mostly sunny, with a high near 67.

 

Forecast from NOAA-NWS for Fullerton CA.