Delaware County (Glen Mills)
September
Weather in Delaware County, Pennsylvania for September 2026
Your guide to Delaware County weather in September - trends and predictions
Gale Watch - See hour by hour.
So far, September 2026 in Delaware County is slightly warmer than the historical average by 1.7 °F.
The forecast for the upcoming days in Delaware County predicts a temperature of 17.7 °F, which is slightly above the historical average.
In general, the average temperature in Delaware County at the beginning of September is 26.6 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 16.3 °F by the end of September.
The climate of Delaware County in September is notably wet, with an average of 13 rainy days, and a total of 247.5 mm of precipitation.
New! Chat with our AI weatherman - it’s amazing and free.
Official Weather Alert ⚠️
Temperatures
Rain 🌧️
More
17
Dry days
13
Rainy days
0
Snow days
24°/16°
Temperatures
14 km/h
Avg max wind
73 %
Avg humidity
Delaware County Weather September
Move between months or click on a day
Temperatures trend during September in Delaware County
See the weather trend as well as the moving average line
September weather in Delaware County day by day
Click on a date for more information
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Light rain shower | 29° /19° | 1 mm | 6 | |
| Sept. 2 |  Overcast | 25° /17° | 1.3 mm | 4 | |
| Sept. 3 |  Sunny | 25° /15° | 8.1 mm | 4 | |
| Sept. 4 | Overcast | 28° /16° | 0.5 mm | 6 | |
| Sept. 5 |  Partly cloudy | 29° /17° | 16.6 mm | 6 | |
| Sept. 6 | Light rain shower | 27° /17° | 4.4 mm | 7 | |
| Sept. 7 |  Fog | 23° /14° | 27.5 mm | 6 | |
| Sept. 8 | Sunny | 25° /11° | 0 mm | 7 | |
| Sept. 9 | Overcast | 26° /14° | 0 mm | 5 | |
| Sept. 10 | Overcast | 26° /16° | 0 mm | 5 | |
| Sept. 11 | Sunny | 27° /16° | 0.3 mm | 5 | |
| Sept. 12 | Sunny | 27° /15° | 0 mm | 6 | |
| Sept. 13 | Partly cloudy | 26° /16° | 5.2 mm | 5 | |
| Sept. 14 | Partly cloudy | 27° /17° | 0.1 mm | 7 | |
| Sept. 15 | Partly cloudy | 26° /15° | 0 mm | 7 | |
| Sept. 16 | Overcast | 25° /14° | 0 mm | 6 | |
| Sept. 17 | Overcast | 23° /16° | 3 mm | 4 | |
| Sept. 18 | Mist | 25° /17° | 0.2 mm | 5 | |
| Sept. 19 |  Heavy rain | 24° /15° | 52.2 mm | 5 | |
| Sept. 20 | Overcast | 22° /17° | 7.9 mm | 4 | |
| Sept. 21 | Light rain shower | 20° /13° | 17.2 mm | 5 | |
| Sept. 22 | Light rain shower | 14° /11° | 17.1 mm | 0.5 | |
| Sept. 23 | Overcast | 15° /9° | 6.9 mm | 3.9 | |
| Sept. 24 | Overcast | 14° /10° | 5.6 mm | 3.1 | |
| Sept. 25 | Overcast | 19° /9° | 0.2 mm | 4 | |
| Sept. 26 | Light rain shower | 11° /10° | 4.6 mm | 3 | |
| Sept. 27 | Overcast | 16° /11° | 0.1 mm | 5 | |
| Sept. 28 | Overcast | 15° /12° | 0.9 mm | 3 | |
| Sept. 29 | Patchy rain possible | 18° /14° | 3.4 mm | 4 | |
| Sept. 30 | Patchy rain possible | 21° /16° | 0.7 mm | 5 | |
| Next | |||||
Important Notice
Our weather forecast for Delaware 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 Delaware County forecast closer to your planned date for the most up-to-date weather information.
Change Month
Delaware County in September - FAQ
What are the expected maximum and minimum temperatures in Delaware County during September?
During September, expect a variety of temperatures with highs around 24° and lows near 16°, suitable for diverse activities and preferences.
How much rainfall should be expected in Delaware County during September?
Significant rainfall exceeding 247.5 mm is expected in Delaware County during September, occurring over more than 13 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Delaware County during September?
The average wind speed in Delaware County during September is 14 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Delaware County
Explore the daily rainfall trends and prepare for Delaware Countys September weather 💧
Typically, Delaware County has 13 rainy days in September with a total of 247.5 mm of rainfall.
UV exposure in Delaware County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
Top locations in Delaware County
Select a location for an accurate weather forecast
More Locations Quick links
More Delaware County weather pages
You are here
Where is Delaware County?Get accurate weather forecasts for Delaware County, located at latitude 39.919 and longitude -75.492. Stay updated with localized weather information tailored for Delaware County.
Found a mistake?
We appreciate your attention to details. Tell us here.