New Castle County
September
Weather in New Castle County for September 2025
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 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 New Castle County 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
New Castle County 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 New Castle County
See the weather trend as well as the moving average line
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 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.
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 26° and lows near 15°, suitable for diverse activities and preferences.
How much rainfall should be expected in New Castle County during September?
Significant rainfall exceeding 197.4 mm is expected in New Castle County during September, occurring over more than 14 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 15 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 💧
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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