New Castle County (Wilmington)
September
Weather in New Castle County, Delaware for September 2026
Your guide to New Castle County weather in September - trends and predictions
In general, the average temperature in New Castle County at the beginning of September is 26.6 °C. As the month progressed, temperatures tended to moderately fall, reaching an average of 24.7 °C by the end of September.
New Castle County experiences moderate rainfall in September, with an average of 8 rainy days and a total precipitation of 219.9 mm.
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Temperatures
Rain 🌧️
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22
Dry days
8
Rainy days
0
Snow days
25°/17°
Temperatures
13 km/h
Avg max wind
71 %
Avg humidity
New Castle County Weather September
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Temperatures trend during September in New Castle County
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September weather in New Castle County day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| Sept. 1 |  Overcast | 24° /17° | 0 mm | 4 | |
| Sept. 2 |  Sunny | 27° /17° | 0 mm | 8 | |
| Sept. 3 | Overcast | 23° /16° | 0 mm | 6 | |
| Sept. 4 |  Mist | 29° /16° | 0 mm | 8 | |
| Sept. 5 | Mist | 32° /19° | 22.5 mm | 7 | |
| Sept. 6 |  Light rain shower | 31° /21° | 21.9 mm | 7 | |
| Sept. 7 |  Moderate or heavy rain shower | 20° /14° | 81.6 mm | 4 | |
| Sept. 8 | Sunny | 23° /13° | 0 mm | 8 | |
| Sept. 9 |  Cloudy | 23° /15° | 0 mm | 8 | |
| Sept. 10 | Overcast | 21° /16° | 0 mm | 2 | |
| Sept. 11 |  Partly cloudy | 26° /15° | 0 mm | 7 | |
| Sept. 12 | Partly cloudy | 25° /17° | 0 mm | 7 | |
| Sept. 13 | Mist | 25° /17° | 0 mm | 5 | |
| Sept. 14 | Overcast | 28° /18° | 0 mm | 7 | |
| Sept. 15 | Moderate rain at times | 26° /18° | 3.5 mm | 7 | |
| Sept. 16 | Overcast | 24° /15° | 0 mm | 7 | |
| Sept. 17 | Moderate rain at times | 19° /15° | 3.6 mm | 1 | |
| Sept. 18 | Overcast | 27° /18° | 0 mm | 4 | |
| Sept. 19 | Partly cloudy | 31° /18° | 0 mm | 6 | |
| Sept. 20 | Overcast | 20° /16° | 0 mm | 3 | |
| Sept. 21 | Overcast | 21° /15° | 0 mm | 3 | |
| Sept. 22 | Overcast | 24° /16° | 0 mm | 3 | |
| Sept. 23 | Fog | 28° /18° | 0 mm | 3 | |
| Sept. 24 | Mist | 28° /18° | 0 mm | 4 | |
| Sept. 25 | Light rain shower | 26° /19° | 40.4 mm | 1 | |
| Sept. 26 | Mist | 24° /19° | 5.6 mm | 4 | |
| Sept. 27 | Mist | 25° /16° | 0 mm | 4 | |
| Sept. 28 |  Moderate rain | 20° /17° | 40.8 mm | 1 | |
| Sept. 29 | Fog | 25° /17° | 0 mm | 2 | |
| Sept. 30 | Overcast | 25° /17° | 0 mm | 1 | |
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Important Notice
Our weather forecast for New Castle 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 New Castle County forecast closer to your planned date for the most up-to-date weather information.
Change Month
New Castle County in September - FAQ
What are the expected maximum and minimum temperatures in New Castle County during September?
During September, expect a variety of temperatures with highs around 25° and lows near 17°, suitable for diverse activities and preferences.
How much rainfall should be expected in New Castle County during September?
Significant rainfall exceeding 219.9 mm is expected in New Castle County during September, occurring over more than 8 days. Preparing for wet conditions is recommended in your planning.
What are the typical wind conditions in New Castle County during September?
The average wind speed in New Castle County during September is 13 km/h, suggesting breezy to windy conditions, depending on your activities.
September rainfall patterns in New Castle County
Explore the daily rainfall trends and prepare for New Castle Countys September weather 💧
Typically, New Castle County has 8 rainy days in September with a total of 219.9 mm of rainfall.
UV exposure in New Castle County during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
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Where is New Castle County?Get accurate weather forecasts for New Castle County, located at latitude 39.746 and longitude -75.547. Stay updated with localized weather information tailored for New Castle County.
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