Portland
September
Weather in Portland for September 2025
Your guide to Portland weather in September - trends and predictions
In general, the average temperature in Portland 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.
Portland sees moderate rainfall in September, averaging 10 rainy days.
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20
Dry days
10
Rainy days
0
Snow days
24°/12°
Temperatures
11 km/h
Avg max wind
63 %
Avg humidity
Portland in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  30° | 2  27° | 3  25° | 4  25° | 5 30° | 6  30° | 7 28° |
| 8 29° | 9 28° | 10  27° | 11 21° | 12 23° | 13 23° | 14 27° |
| 15 28° | 16 27° | 17 21° | 18 21° | 19 20° | 20 20° | 21 24° |
| 22 24° | 23 23° | 24  25° | 25 20° | 26 21° | 27 19° | 28 19° |
| 29 19° | 30 21° |
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Temperatures trend during September in Portland
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 | 30° /16° | 0.2 mm | 7 | |
| Sept. 2 | Cloudy | 27° /15° | 0.1 mm | 6 | |
| Sept. 3 | Patchy rain possible | 25° /15° | 1.2 mm | 6 | |
| Sept. 4 | Overcast | 25° /12° | 1.1 mm | 6 | |
| Sept. 5 | Overcast | 30° /13° | 0 mm | 7 | |
| Sept. 6 | Partly cloudy | 30° /15° | 0 mm | 8 | |
| Sept. 7 | Cloudy | 28° /15° | 0 mm | 6 | |
| Sept. 8 | Overcast | 29° /14° | 0 mm | 7 | |
| Sept. 9 | Cloudy | 28° /12° | 0 mm | 7 | |
| Sept. 10 | Sunny | 27° /13° | 0 mm | 7 | |
| Sept. 11 | Overcast | 21° /13° | 5.5 mm | 5 | |
| Sept. 12 | Cloudy | 23° /12° | 0.3 mm | 6 | |
| Sept. 13 | Overcast | 23° /11° | 0 mm | 6 | |
| Sept. 14 | Sunny | 27° /11° | 0.1 mm | 7 | |
| Sept. 15 | Sunny | 28° /12° | 0 mm | 7 | |
| Sept. 16 | Sunny | 27° /11° | 0 mm | 7 | |
| Sept. 17 | Overcast | 21° /11° | 6.1 mm | 5 | |
| Sept. 18 | Overcast | 21° /13° | 0 mm | 5 | |
| Sept. 19 | Overcast | 20° /12° | 0 mm | 5 | |
| Sept. 20 | Light rain shower | 20° /11° | 0.7 mm | 5 | |
| Sept. 21 | Partly cloudy | 24° /9° | 0 mm | 7 | |
| Sept. 22 | Sunny | 24° /12° | 0 mm | 7 | |
| Sept. 23 | Light rain shower | 23° /13° | 0.8 mm | 5 | |
| Sept. 24 | Light drizzle | 25° /13° | 2.2 mm | 6 | |
| Sept. 25 | Light rain shower | 20° /14° | 7 mm | 5 | |
| Sept. 26 | Light rain shower | 21° /12° | 5.3 mm | 5 | |
| 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.
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 12°. 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 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 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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