Delaware
September
Weather in Delaware for September 2025
Your guide to Delaware weather in September - trends and predictions
In general, the average temperature in Delaware at the beginning of September is 28.7 °F. As the month progressed, temperatures tended to significantly cool down, reaching an average of 20.3 °F by the end of September.
The climate of Delaware in September is notably wet, with an average of 14 rainy days.
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16
Dry days
14
Rainy days
0
Snow days
26°/15°
Temperatures
15 km/h
Avg max wind
74 %
Avg humidity
Delaware in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  28° | 2 26° | 3  28° | 4  30° | 5  31° | 6 30° | 7 28° |
| 8 28° | 9 28° | 10  28° | 11  28° | 12 28° | 13  25° | 14 27° |
| 15 27° | 16 26° | 17  23° | 18 22° | 19 22° | 20 22° | 21 25° |
| 22 21° | 23 19° | 24 19° | 25  19° | 26 21° | 27  22° | 28 22° |
| 29 18° | 30 21° |
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Temperatures trend during September in Delaware
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September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 | Sunny | 28° /16° | 2.3 mm | 7 | |
| Sept. 2 | Sunny | 26° /15° | 0 mm | 6 | |
| Sept. 3 | Partly cloudy | 28° /14° | 0 mm | 7 | |
| Sept. 4 | Thundery outbreaks possible | 30° /17° | 0 mm | 7 | |
| Sept. 5 | Cloudy | 31° /17° | 0 mm | 8 | |
| Sept. 6 | Sunny | 30° /19° | 0.7 mm | 7 | |
| Sept. 7 | Thundery outbreaks possible | 28° /17° | 1.3 mm | 7 | |
| Sept. 8 | Thundery outbreaks possible | 28° /14° | 3.3 mm | 7 | |
| Sept. 9 | Thundery outbreaks possible | 28° /14° | 8.1 mm | 7 | |
| Sept. 10 | Moderate or heavy rain shower | 28° /17° | 7 mm | 7 | |
| Sept. 11 | Light rain shower | 28° /17° | 2.8 mm | 7 | |
| Sept. 12 | Moderate rain at times | 28° /16° | 1.8 mm | 7 | |
| Sept. 13 | Torrential rain shower | 25° /16° | 11.8 mm | 6 | |
| Sept. 14 | Sunny | 27° /15° | 0 mm | 7 | |
| Sept. 15 | Sunny | 27° /13° | 0 mm | 7 | |
| Sept. 16 | Sunny | 26° /13° | 0 mm | 7 | |
| Sept. 17 | Moderate rain | 23° /15° | 3.7 mm | 5 | |
| Sept. 18 | Light rain shower | 22° /16° | 2.2 mm | 5 | |
| Sept. 19 | Sunny | 22° /13° | 79.8 mm | 6 | |
| Sept. 20 | Partly cloudy | 22° /15° | 0 mm | 6 | |
| Sept. 21 | Cloudy | 25° /15° | 12.1 mm | 6 | |
| Sept. 22 | Patchy rain possible | 21° /14° | 0 mm | 5 | |
| Sept. 23 | Light rain shower | 19° /14° | 19.1 mm | 5 | |
| Sept. 24 | Moderate rain | 19° /15° | 22.8 mm | 5 | |
| Sept. 25 | Light drizzle | 19° /15° | 17.6 mm | 5 | |
| Sept. 26 | Patchy rain possible | 21° /16° | 0 mm | 5 | |
| Sept. 27 | Overcast | 22° /16° | 0 mm | 5 | |
| Sept. 28 | Patchy rain possible | 22° /14° | 6.1 mm | 5 | |
| Sept. 29 | Light rain shower | 18° /15° | 20.7 mm | 5 | |
| Sept. 30 | Light rain | 21° /15° | 0.7 mm | 5 | |
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Important Notice
Our weather forecast for Delaware 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 forecast closer to your planned date for the most up-to-date weather information.
Delaware in September - FAQ
What are the expected maximum and minimum temperatures in Delaware during September?
During September, expect a variety of temperatures with highs around 26° and lows near 15°, suitable for diverse activities and preferences.
How much rainfall should be expected in Delaware during September?
Significant rainfall exceeding 197.4 mm is expected in Delaware during September, occurring over more than 14 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in Delaware during September?
The average wind speed in Delaware during September is 15 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in Delaware
Explore the daily rainfall trends and prepare for Delawares September weather 💧
UV exposure in Delaware during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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