Portland (OR)
September
Weather in Portland, Oregon for September 2025
Your guide to Portland weather in September - trends and predictions
Until now, September 2025 in Portland is slightly cooler than the historical average by -1.3 °F.
Expect cooler weather in the next days in Portland with the forecast suggesting a temperature of 23.9 °F, lower than the historical average.
In general, the average temperature in Portland at the beginning of September is 28.1 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 19.3 °F by the end of September.
Portland experiences moderate rainfall in September, with an average of 8 rainy days and a total precipitation of 37 mm.
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Temperatures
Rain 🌧️
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22
Dry days
8
Rainy days
0
Snow days
24°/13°
Temperatures
11 km/h
Avg max wind
62 %
Avg humidity
Portland Weather September
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Temperatures trend during September in Portland
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September weather in Portland day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Fog | 28° /15° | 0.1 mm | 6 | |
| Sept. 2 |  Cloudy | 28° /15° | 0.1 mm | 7 | |
| Sept. 3 |  Patchy rain possible | 27° /16° | 0.8 mm | 6 | |
| Sept. 4 |  Overcast | 28° /13° | 0.7 mm | 6 | |
| Sept. 5 | Overcast | 32° /16° | 0 mm | 8 | |
| Sept. 6 |  Partly cloudy | 29° /16° | 0 mm | 7 | |
| Sept. 7 | Overcast | 25° /15° | 0 mm | 6 | |
| Sept. 8 | Overcast | 26° /15° | 5.2 mm | 6 | |
| Sept. 9 | Cloudy | 26° /13° | 10.2 mm | 6 | |
| Sept. 10 |  Sunny | 25° /14° | 0 mm | 6 | |
| Sept. 11 | Overcast | 20° /13° | 3.7 mm | 4 | |
| Sept. 12 | Cloudy | 21° /12° | 0.2 mm | 5 | |
| Sept. 13 | Overcast | 26° /14° | 0 mm | 1.4 | |
| Sept. 14 | Cloudy | 20° /15° | 0 mm | 0.8 | |
| Sept. 15 | Overcast | 24° /13° | 0 mm | 1.3 | |
| Sept. 16 | Sunny | 34° /12° | 0 mm | 1.4 | |
| Sept. 17 | Sunny | 25° /14° | 0 mm | 0 | |
| Sept. 18 | Sunny | 24° /11° | 0 mm | 5 | |
| Sept. 19 | Sunny | 27° /10° | 0 mm | 5 | |
| Sept. 20 | Sunny | 27° /13° | 0 mm | 5 | |
| Sept. 21 | Patchy rain possible | 20° /14° | 0.1 mm | 4 | |
| Sept. 22 | Sunny | 22° /11° | 0 mm | 5 | |
| Sept. 23 | Sunny | 29° /10° | 0 mm | 5 | |
| Sept. 24 | Patchy rain possible | 20° /16° | 0.2 mm | 4 | |
| Sept. 25 | Patchy rain possible | 17° /15° | 0.5 mm | 4 | |
| Sept. 26 | Patchy rain possible | 20° /13° | 2.7 mm | 4 | |
| Sept. 27 | Light rain shower | 19° /13° | 6.3 mm | 5 | |
| Sept. 28 | Patchy rain possible | 19° /11° | 0.2 mm | 5 | |
| Sept. 29 | Overcast | 19° /9° | 0 mm | 4 | |
| Sept. 30 | Partly cloudy | 21° /8° | 0 mm | 6 | |
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Important Notice
Our weather forecast for Portland 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 Portland forecast closer to your planned date for the most up-to-date weather information.
Change Month
Portland in September - FAQ
What are the expected maximum and minimum temperatures in Portland during September?
Enjoy moderate daytime temperatures of up to 24° and cooler nights around 13°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Portland during September?
In September, Portland can expect light to moderate rainfall, totaling 37 mm across approximately 8 days. Occasional showers are possible, and planning ahead for them could be helpful.
What are the typical wind conditions in Portland during September?
The average wind speed in Portland during September is 11 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Portland
Explore the daily rainfall trends and prepare for Portlands September weather 💧
UV exposure in Portland during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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