Walla Walla Weather in September

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

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

September is in the fall / autumn in Walla Walla and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a comfortable 25°C (78°F), whilst at night 10°C (51°F) is normal.

Walla Walla weather averages (imperial / metric)
Daytime temperature 25.3°C 77.5°F
Nightly temperature 10.3°C 50.5°F
Average temperature 17.8°C 64°F
Daily sunshine 9.7 hrs
Avg rainfall 20 mm 0.8 ins
Rainy days 5 days
Sea temperature 13.1°C 55.6°F
Humidity 49%
Windspeed 13.3kph 8 mph

On average September is the 3rd driest month of the year in Walla Walla with around 20mm 0.8 inches of rain making it a dry time to visit. This rainfall is typically spread over 5 days, although this may vary considerably.

On the flip side this corresponds to an average of 9.7 hours of sunshine per day.

September temperatures in Walla Walla

Walla Walla average temperature in September

September rainfall

Walla Walla average rain in September

September hourly sunshine

Walla Walla 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 Walla Walla 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

Walla Walla weather stats

Walla Walla weather statistics
Hottest month: July 31.2°C 88.2°F
Driest month: July 12mm 0.5ins
Sunniest month: July 13.4hrs
Coldest month: January 4.8°C 40.6°F
Wettest month: November 57mm 2.2ins
Map showing location of Walla Walla (46.06458, -118.34302) Walla Walla map pin © Google

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