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Weather in Multnomah County for September 2025

Your guide to Multnomah County weather in September - trends and predictions
  • In general, the average temperature in Multnomah County at the beginning of September is 27.9 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 20.6 °F by the end of September.

  • Multnomah County sees moderate rainfall in September, averaging 10 rainy days.

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Average dry days
20
Dry days
Average rainy days
10
Rainy days
Average snowy days
0
Snow days
Average temperatures
24°/12°
Temperatures
Average wind speed
11 km/h
Avg max wind
Average humidity
63 %
Avg humidity

Multnomah County in September average weather

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Temperatures trend during September in Multnomah County

See the weather trend as well as the moving average line

September weather day by day

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Date Weather Temperatures Rain UV More
Sept. 1 Fog
Fog
30° /16° 0.2 mm 7
Sept. 2 Cloudy
Cloudy
27° /15° 0.1 mm 6
Sept. 3 Patchy rain possible
Patchy rain possible
25° /15° 1.2 mm 6
Sept. 4 Overcast
Overcast
25° /12° 1.1 mm 6
Sept. 5 Overcast
Overcast
30° /13° 0 mm 7
Sept. 6 Partly cloudy
Partly cloudy
30° /15° 0 mm 8
Sept. 7 Cloudy
Cloudy
28° /15° 0 mm 6
Sept. 8 Overcast
Overcast
29° /14° 0 mm 7
Sept. 9 Cloudy
Cloudy
28° /12° 0 mm 7
Sept. 10 Sunny
Sunny
27° /13° 0 mm 7
Sept. 11 Overcast
Overcast
21° /13° 5.5 mm 5
Sept. 12 Cloudy
Cloudy
23° /12° 0.3 mm 6
Sept. 13 Overcast
Overcast
23° /11° 0 mm 6
Sept. 14 Sunny
Sunny
27° /11° 0.1 mm 7
Sept. 15 Sunny
Sunny
28° /12° 0 mm 7
Sept. 16 Sunny
Sunny
27° /11° 0 mm 7
Sept. 17 Overcast
Overcast
21° /11° 6.1 mm 5
Sept. 18 Overcast
Overcast
21° /13° 0 mm 5
Sept. 19 Overcast
Overcast
20° /12° 0 mm 5
Sept. 20 Light rain shower
Light rain shower
20° /11° 0.7 mm 5
Sept. 21 Partly cloudy
Partly cloudy
24° /9° 0 mm 7
Sept. 22 Sunny
Sunny
24° /12° 0 mm 7
Sept. 23 Light rain shower
Light rain shower
23° /13° 0.8 mm 5
Sept. 24 Light drizzle
Light drizzle
25° /13° 2.2 mm 6
Sept. 25 Light rain shower
Light rain shower
20° /14° 7 mm 5
Sept. 26 Light rain shower
Light rain shower
21° /12° 5.3 mm 5
Sept. 27 Light rain shower
Light rain shower
19° /13° 6.3 mm 5
Sept. 28 Patchy rain possible
Patchy rain possible
19° /11° 0.2 mm 5
Sept. 29 Overcast
Overcast
19° /9° 0 mm 4
Sept. 30 Partly cloudy
Partly cloudy
21° /8° 0 mm 6
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Important Notice
Our weather forecast for Multnomah County in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Multnomah County forecast closer to your planned date for the most up-to-date weather information.

Multnomah County in September - FAQ

What are the expected maximum and minimum temperatures in Multnomah County during September?
Enjoy moderate daytime temperatures of up to 24° and cooler nights around 12°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Multnomah County during September?
In September, Multnomah County can expect light to moderate rainfall, totaling 50 mm across approximately 10 days. Occasional showers are possible, and planning ahead for them could be helpful.
What are the typical wind conditions in Multnomah County during September?
The average wind speed in Multnomah County during September is 11 km/h, suggesting breezy to windy conditions, depending on your activities.

September rainfall patterns in Multnomah County

Explore the daily rainfall trends and prepare for Multnomah Countys September weather 💧

UV exposure in Multnomah County during September

Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Location coordinates Where is Multnomah County?

Get accurate weather forecasts for Multnomah County, located at latitude 45.523 and longitude -122.676. Stay updated with localized weather information tailored for Multnomah County.

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