Mount Rainier (WA)
September
Weather in Mount Rainier, Washington for September 2027
Your guide to Mount Rainier weather in September - trends and predictions
In general, the average temperature in Mount Rainier at the beginning of September is 19.3 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 16.1 °F by the end of September.
The climate of Mount Rainier in September is notably wet, with an average of 15 rainy days, and a total of 77.7 mm of precipitation.
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Temperatures
Rain 🌧️
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15
Dry days
15
Rainy days
0
Snow days
19°/9°
Temperatures
11 km/h
Avg max wind
69 %
Avg humidity
Mount Rainier Weather September
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Temperatures trend during September in Mount Rainier
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September weather in Mount Rainier day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Patchy rain possible | 20° /11° | 0.3 mm | 2 | |
| Sept. 2 |  Moderate or heavy rain shower | 18° /11° | 6.9 mm | 2 | |
| Sept. 3 | Moderate or heavy rain shower | 17° /10° | 7.2 mm | 3 | |
| Sept. 4 | Moderate rain at times | 18° /9° | 2.8 mm | 1 | |
| Sept. 5 | Patchy rain possible | 20° /8° | 0.3 mm | 2 | |
| Sept. 6 | Patchy rain possible | 21° /8° | 0.1 mm | 4 | |
| Sept. 7 | Patchy rain possible | 21° /11° | 0.9 mm | 2 | |
| Sept. 8 |  Sunny | 23° /9° | 0 mm | 6 | |
| Sept. 9 |  Overcast | 25° /11° | 0 mm | 5 | |
| Sept. 10 | Overcast | 21° /10° | 0 mm | 2 | |
| Sept. 11 | Overcast | 19° /9° | 0 mm | 2 | |
| Sept. 12 | Patchy rain possible | 19° /10° | 2.9 mm | 1 | |
| Sept. 13 | Moderate or heavy rain shower | 12° /9° | 20.1 mm | 1 | |
| Sept. 14 | Patchy rain possible | 18° /11° | 2 mm | 1 | |
| Sept. 15 |  Heavy rain at times | 17° /9° | 2.9 mm | 2 | |
| Sept. 16 | Sunny | 22° /8° | 0 mm | 5 | |
| Sept. 17 |  Cloudy | 24° /11° | 0 mm | 5 | |
| Sept. 18 | Sunny | 21° /10° | 0 mm | 5 | |
| Sept. 19 | Overcast | 20° /10° | 0 mm | 4 | |
| Sept. 20 | Sunny | 21° /10° | 0 mm | 4 | |
| Sept. 21 | Overcast | 20° /10° | 0 mm | 4 | |
| Sept. 22 | Moderate rain at times | 20° /10° | 1.2 mm | 2 | |
| Sept. 23 | Overcast | 18° /8° | 0 mm | 1 | |
| Sept. 24 | Patchy rain possible | 16° /8° | 3.6 mm | 1 | |
| Sept. 25 | Moderate or heavy rain shower | 13° /9° | 19 mm | 1 | |
| Sept. 26 | Overcast | 16° /6° | 0 mm | 2 | |
| Sept. 27 | Overcast | 17° /5° | 0 mm | 3 | |
| Sept. 28 | Overcast | 18° /7° | 0 mm | 2 | |
| Sept. 29 | Moderate rain at times | 15° /12° | 2.7 mm | 1 | |
| Sept. 30 | Moderate rain at times | 18° /8° | 2.4 mm | 2 | |
| Next | |||||
Important Notice
Our weather forecast for Mount Rainier 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 Mount Rainier forecast closer to your planned date for the most up-to-date weather information.
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Mount Rainier in September - FAQ
What are the expected maximum and minimum temperatures in Mount Rainier during September?
Enjoy moderate daytime temperatures of up to 19° and cooler nights around 9°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Mount Rainier during September?
Moderate rainfall is anticipated in Mount Rainier during September, with a total of 77.7 mm spread over approximately 15 days. Considering plans for rainy days is advisable.
What are the typical wind conditions in Mount Rainier during September?
The average wind speed in Mount Rainier during September is 11 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Mount Rainier
Explore the daily rainfall trends and prepare for Mount Rainiers September weather 💧
Typically, Mount Rainier has 15 rainy days in September with a total of 77.7 mm of rainfall.
UV exposure in Mount Rainier during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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