Richland Weather in September

What's the weather like in Richland (Washington) in September 2025?

The climate in Richland during September can be summarized as mild and very dry.

September is in the fall / autumn in Richland and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a comfortable 26°C (79°F), whilst at night 10°C (49°F) is normal.

Richland weather averages (imperial / metric)
Daytime temperature 26.1°C 79°F
Nightly temperature 9.5°C 49.1°F
Average temperature 17.8°C 64°F
Daily sunshine 9.5 hrs
Avg rainfall 9 mm 0.4 ins
Rainy days 4 days
Sea temperature 13°C 55.4°F
Humidity 51%
Windspeed 13kph 8 mph

On average September is the 3rd driest month of the year in Richland with around 9mm 0.4 inches of rain making it a very dry time to visit.

On the flip side this corresponds to an average of 9.5 hours of sunshine per day.

September temperatures in Richland

Richland average temperature in September

September rainfall

Richland average rain in September

September hourly sunshine

Richland 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 Richland 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

Richland weather stats

Richland weather statistics
Hottest month: July 31.5°C 88.7°F
Driest month: July 5mm 0.2ins
Sunniest month: July 12.9hrs
Coldest month: January 4.3°C 39.7°F
Wettest month: December 28mm 1.1ins
Map showing location of Richland (46.28569, -119.28446) Richland map pin © Google

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