Fairfield Weather in September

What's the weather like in Fairfield (California) in September 2025?

The climate in Fairfield during September can be summarized as warm and very dry.

September is in the fall / autumn in Fairfield and is typically the 3rd warmest month of the year. Daytime maximum temperatures average around a comfortable 29°C (84°F), whilst at night 12°C (53°F) is normal.

Fairfield weather averages (imperial / metric)
Daytime temperature 28.7°C 83.6°F
Nightly temperature 11.8°C 53.2°F
Average temperature 20.2°C 68.4°F
Daily sunshine 11 hrs
Avg rainfall 8 mm 0.3 ins
Rainy days 2 days
Sea temperature 14.4°C 57.9°F
Humidity 63%
Windspeed 14.8kph 9 mph

On average September is the 4th driest month of the year in Fairfield with around 8mm 0.3 inches of rain making it a very dry time to visit.

On the flip side this corresponds to an average of 11 hours of sunshine per day.

September temperatures in Fairfield

Fairfield average temperature in September

September rainfall

Fairfield average rain in September

September hourly sunshine

Fairfield average rain in September

The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Fairfield in September 2025.

Other monthly averages

Best places to visit in September

UV index Best time to go?

Beta

Current (hourly) weather 15 day forecast

Fairfield weather stats

Fairfield weather statistics
Hottest month: July 30.3°C 86.5°F
Driest month: July 1mm 0ins
Sunniest month: July 12.9hrs
Coldest month: January 12.4°C 54.3°F
Wettest month: January 136mm 5.4ins
Map showing location of Fairfield (38.24936, -122.03997) Fairfield map pin © Google

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