Portland Weather in September

What's the weather like in Portland (Oregon) in September 2025?

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

September is in the fall / autumn in Portland and is typically the 4th warmest month of the year. Daytime maximum temperatures average around a comfortable 23°C (73°F), whilst at night 9°C (49°F) is normal.

Portland weather averages (imperial / metric)
Daytime temperature 22.9°C 73.2°F
Nightly temperature 9.3°C 48.7°F
Average temperature 16.1°C 61°F
Daily sunshine 8.5 hrs
Avg rainfall 47 mm 1.9 ins
Rainy days 8 days
Sea temperature 13.3°C 55.9°F
Humidity 70%
Windspeed 11.5kph 7 mph

On average September is the 4th driest month of the year in Portland with around 47mm 1.9 inches of rain making it a reasonably dry 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 8.5 hours of sunshine per day.

September temperatures in Portland

Portland average temperature in September

September rainfall

Portland average rain in September

September hourly sunshine

Portland 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 Portland 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

Portland weather stats

Portland weather statistics
Hottest month: August 25.5°C 77.9°F
Driest month: July 18mm 0.7ins
Sunniest month: July 11.4hrs
Coldest month: January 7°C 44.6°F
Wettest month: December 179mm 7ins
Map showing location of Portland (45.52345, -122.67621) Portland map pin © Google

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