Union Weather in September

What's the weather like in Union (South Carolina) in September 2025?

The climate in Union during September can be summarized as warm, humid and damp.

September is in the fall / autumn in Union and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a muggy 28°C (83°F), whilst at night 17°C (62°F) is normal.

Union weather averages (imperial / metric)
Daytime temperature 28.2°C 82.7°F
Nightly temperature 16.5°C 61.6°F
Average temperature 22.3°C 72.1°F
Daily sunshine 8.4 hrs
Avg rainfall 101 mm 4 ins
Rainy days 8 days
Sea temperature 25.9°C 78.6°F
Humidity 75%
Windspeed 10.4kph 7 mph

On average September is the 6th driest month of the year in Union with around 101mm 4 inches of rain making it a damp time to visit. This rainfall is typically spread over 8 days, although this may vary considerably.

On the flip side this corresponds to an average of 8.4 hours of sunshine per day.

September temperatures in Union

Union average temperature in September

September rainfall

Union average rain in September

September hourly sunshine

Union 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 Union 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

Union weather stats

Union weather statistics
Hottest month: July 31.9°C 89.4°F
Driest month: April 82mm 3.2ins
Sunniest month: April 9.4hrs
Coldest month: January 10.8°C 51.4°F
Wettest month: March 132mm 5.2ins
Map showing location of Union (34.71541, -81.62371) Union map pin © Google

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