NWS Forecast for Fountain Valley CA

National Weather Service Forecast for: Fountain Valley CA
Issued by: National Weather Service San Diego, CA

Updated: 1:29 pm PST Dec 16, 2025

Tonight Patchy Fog	Wednesday Areas Fog	Wednesday Night Patchy Fog	Thursday Patchy Fog	Thursday Night Mostly Clear then Patchy Fog	Friday Patchy Fog then Mostly Sunny	Friday Night Patchy Fog	Saturday Patchy Fog then Mostly Sunny	Saturday Night Patchy Fog
Lo 51 °F	Hi 70 °F	Lo 51 °F	Hi 76 °F	Lo 53 °F	Hi 74 °F	Lo 52 °F	Hi 70 °F	Lo 53 °F

Air Quality Alert
Dense Fog Advisory

Tonight	Patchy fog. Otherwise, mostly cloudy, with a low around 51. Calm wind.
Wednesday	Areas of fog before 1pm. Otherwise, mostly cloudy, then gradually becoming sunny, with a high near 70. Calm wind becoming southwest around 5 mph in the afternoon.
Wednesday Night	Patchy fog. Otherwise, increasing clouds, with a low around 51. Southeast wind around 5 mph becoming calm.
Thursday	Patchy fog. Otherwise, mostly cloudy, then gradually becoming sunny, with a high near 76. Calm wind becoming west around 5 mph in the afternoon.
Thursday Night	Patchy fog after 4am. Otherwise, mostly clear, with a low around 53. Calm wind.
Friday	Patchy fog before 10am. Otherwise, mostly sunny, with a high near 74.
Friday Night	Patchy fog. Otherwise, increasing clouds, with a low around 52.
Saturday	Patchy fog before 10am. Otherwise, partly sunny, with a high near 70.
Saturday Night	Patchy fog. Otherwise, mostly cloudy, with a low around 53.
Sunday	Patchy fog before 10am. Otherwise, partly sunny, with a high near 70.
Sunday Night	Patchy fog. Otherwise, mostly cloudy, with a low around 53.
Monday	Patchy fog. Otherwise, partly sunny, with a high near 71.
Monday Night	Patchy fog. Otherwise, mostly cloudy, with a low around 52.
Tuesday	A slight chance of showers. Patchy fog. Otherwise, cloudy through mid morning, then gradual clearing, with a high near 69.

Forecast from NOAA-NWS for Fountain Valley CA.