National Weather Service Forecast for: Fullerton CA
Issued by: National Weather Service San Diego, CA
Updated: 2:58 am PST Dec 22, 2025
 
Today

Today: Areas of fog before 10am. Otherwise, mostly cloudy, with a high near 68. Calm wind becoming southwest around 5 mph in the afternoon.
Areas Fog
then Mostly
Cloudy
 Tonight

Tonight: Cloudy, with a low around 54. Calm wind.
Cloudy

 Tuesday

Tuesday: Rain likely, mainly after 4pm. Cloudy, with a high near 66. Southeast wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Slight Chance
Rain then
Rain Likely
 Tuesday
Night
Tuesday Night: Rain. The rain could be heavy at times. Low around 58. Southeast wind around 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: Rain, with thunderstorms also possible after 10am. Some of the storms could produce heavy rainfall. High near 64. South wind 15 to 20 mph, with gusts as high as 30 mph. Chance of precipitation is 100%. New rainfall amounts between 2 and 3 inches possible.
Heavy Rain

 Wednesday
Night
Wednesday Night: Rain and possibly a thunderstorm. Some of the storms could produce heavy rainfall. Low around 54. Chance of precipitation is 100%.
Heavy Rain

 Christmas
Day
Christmas Day: Rain. High near 64. Chance of precipitation is 90%.
Rain

 Thursday
Night
Thursday Night: Showers. The rain could be heavy at times. Cloudy, with a low around 53.
Heavy Rain

 Friday

Friday: Showers. Mostly cloudy, with a high near 63.
Showers
Hi 68 °F Lo 54 °F Hi 66 °F Lo 58 °F Hi 64 °F Lo 54 °F Hi 64 °F Lo 53 °F Hi 63 °F

Air Quality Alert
Flood Watch
Dense Fog Advisory
 

Today
 
 Areas of fog before 10am. Otherwise, mostly cloudy, with a high near 68. Calm wind becoming southwest around 5 mph in the afternoon.
Tonight
 
 Cloudy, with a low around 54. Calm wind.
Tuesday
 
 Rain likely, mainly after 4pm. Cloudy, with a high near 66. Southeast wind 5 to 10 mph, with gusts as high as 20 mph. Chance of precipitation is 60%. New precipitation amounts of less than a tenth of an inch possible.
Tuesday Night
 
 Rain. The rain could be heavy at times. Low around 58. Southeast wind around 15 mph, with gusts as high as 25 mph. Chance of precipitation is 90%. New precipitation amounts between 1 and 2 inches possible.
Wednesday
 
 Rain, with thunderstorms also possible after 10am. Some of the storms could produce heavy rainfall. High near 64. South wind 15 to 20 mph, with gusts as high as 30 mph. Chance of precipitation is 100%. New rainfall amounts between 2 and 3 inches possible.
Wednesday Night
 
 Rain and possibly a thunderstorm. Some of the storms could produce heavy rainfall. Low around 54. Chance of precipitation is 100%.
Christmas Day
 
 Rain. High near 64. Chance of precipitation is 90%.
Thursday Night
 
 Showers. The rain could be heavy at times. Cloudy, with a low around 53.
Friday
 
 Showers. Mostly cloudy, with a high near 63.
Friday Night
 
 A chance of showers. Mostly cloudy, with a low around 47.
Saturday
 
 A slight chance of showers. Mostly sunny, with a high near 63.
Saturday Night
 
 A slight chance of showers. Partly cloudy, with a low around 46.
Sunday
 
 Mostly sunny, with a high near 66.

 

Forecast from NOAA-NWS for Fullerton CA.