Allentown (PA)
September
Weather in Allentown, Pennsylvania for September 2026
Your guide to Allentown weather in September - trends and predictions
In general, the average temperature in Allentown at the beginning of September is 24.3 °F. As the month progressed, temperatures tended to noticeably cool down, reaching an average of 22 °F by the end of September.
The climate of Allentown in September is notably wet, with an average of 12 rainy days, and a total of 147.1 mm of precipitation.
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Temperatures
Rain 🌧️
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18
Dry days
12
Rainy days
0
Snow days
23°/14°
Temperatures
13 km/h
Avg max wind
75 %
Avg humidity
Allentown Weather September
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Temperatures trend during September in Allentown
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September weather in Allentown day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Moderate or heavy rain shower | 25° /16° | 2.7 mm | 6 | |
| Sept. 2 |  Overcast | 24° /14° | 0 mm | 6 | |
| Sept. 3 |  Sunny | 23° /10° | 0 mm | 6 | |
| Sept. 4 | Sunny | 25° /11° | 5 mm | 6 | |
| Sept. 5 | Sunny | 27° /14° | 11.9 mm | 7 | |
| Sept. 6 | Overcast | 26° /15° | 0 mm | 6 | |
| Sept. 7 | Moderate or heavy rain shower | 20° /12° | 14.8 mm | 5 | |
| Sept. 8 | Sunny | 22° /9° | 0 mm | 6 | |
| Sept. 9 |  Partly cloudy | 23° /9° | 0 mm | 6 | |
| Sept. 10 | Sunny | 23° /10° | 0 mm | 6 | |
| Sept. 11 | Sunny | 25° /11° | 0 mm | 6 | |
| Sept. 12 | Sunny | 25° /13° | 0 mm | 7 | |
| Sept. 13 | Sunny | 25° /14° | 18 mm | 6 | |
| Sept. 14 | Partly cloudy | 29° /14° | 0 mm | 7 | |
| Sept. 15 | Partly cloudy | 26° /14° | 0 mm | 6 | |
| Sept. 16 | Overcast | 24° /12° | 0 mm | 5 | |
| Sept. 17 | Overcast | 22° /14° | 0 mm | 5 | |
| Sept. 18 |  Patchy rain possible | 24° /16° | 0.2 mm | 6 | |
| Sept. 19 | Overcast | 27° /15° | 3.7 mm | 6 | |
| Sept. 20 | Overcast | 22° /14° | 0 mm | 5 | |
| Sept. 21 | Overcast | 22° /14° | 0 mm | 5 | |
| Sept. 22 | Overcast | 23° /14° | 0 mm | 5 | |
| Sept. 23 | Moderate or heavy rain shower | 22° /15° | 7.8 mm | 5 | |
| Sept. 24 | Overcast | 23° /16° | 20 mm | 6 | |
| Sept. 25 | Moderate or heavy rain shower | 21° /16° | 35.2 mm | 5 | |
| Sept. 26 | Moderate rain at times | 24° /17° | 8.1 mm | 6 | |
| Sept. 27 | Moderate or heavy rain shower | 22° /14° | 2.5 mm | 5 | |
| Sept. 28 | Moderate rain at times | 22° /16° | 16.8 mm | 5 | |
| Sept. 29 | Patchy rain possible | 21° /14° | 0.3 mm | 5 | |
| Sept. 30 |  Mist | 21° /14° | 0 mm | 5 | |
| Next | |||||
Important Notice
Our weather forecast for Allentown 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 Allentown forecast closer to your planned date for the most up-to-date weather information.
Change Month
Allentown in September - FAQ
What are the expected maximum and minimum temperatures in Allentown during September?
Enjoy moderate daytime temperatures of up to 23° and cooler nights around 14°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Allentown during September?
Significant rainfall exceeding 147.1 mm is expected in Allentown during September, occurring over more than 12 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Allentown during September?
The average wind speed in Allentown during September is 13 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Allentown
Explore the daily rainfall trends and prepare for Allentowns September weather 💧
Typically, Allentown has 12 rainy days in September with a total of 147.1 mm of rainfall.
UV exposure in Allentown during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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