Vacaville Weather in September

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

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

September is in the fall / autumn in Vacaville and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a comfortable 31°C (88°F), whilst at night 12°C (53°F) is normal.

Vacaville weather averages (imperial / metric)
Daytime temperature 31°C 87.7°F
Nightly temperature 11.7°C 53°F
Average temperature 21.3°C 70.3°F
Daily sunshine 11.5 hrs
Avg rainfall 9 mm 0.3 ins
Rainy days 2 days
Sea temperature 15°C 58.9°F
Humidity 61%
Windspeed 14kph 9 mph

On average September is the 4th driest month of the year in Vacaville with around 9mm 0.3 inches of rain making it a very dry time to visit.

On the flip side this corresponds to an average of 11.5 hours of sunshine per day.

September temperatures in Vacaville

Vacaville average temperature in September

September rainfall

Vacaville average rain in September

September hourly sunshine

Vacaville 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 Vacaville 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

Vacaville weather stats

Vacaville weather statistics
Hottest month: July 33.9°C 93°F
Driest month: July 1mm 0ins
Sunniest month: July 13.6hrs
Coldest month: January 11.9°C 53.4°F
Wettest month: January 138mm 5.4ins
Map showing location of Vacaville (38.35658, -121.98774) Vacaville map pin © Google

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