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September Weather in South New Castle, United States

Last updated: June 24, 2025

In South New Castle, United States, the average temperature in September hovers around 19°C (66°F), offering a pleasant climate. Expect daytime highs to reach a warm 33°C (92°F) while nights could dip to a cool 3°C (38°F). With 115 mm (4.5 in) of precipitation spread over 10 days, it's advisable to keep an umbrella handy. The average humidity of 77% adds a touch of tropical warmth to your experience!

September Temperature in South New Castle

In September in South New Castle, the average temperature is 19°C (66°F). Maximum temperatures can reach 33°C (92°F), while minimums can dip as low as 3°C (38°F). This variety in weather makes South New Castle an ideal destination for travelers seeking both warm and cool experiences.

September Weather in South New Castle: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in South New Castle, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In South New Castle, September typically has an average temperature of 19°C (66°F), with highs reaching up to 33°C (92°F) and lows dropping to around 3°C (38°F).
JanFebMarAprMayJunJulAugSepOctNovDec293339496169737166564135
Data source: Temperature data for South New Castle generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in South New Castle

In South New Castle in September, the precipitation amount is 115 mm (4.5 in) over a span of 10 days.

September Precipitation Trends in South New Castle

The chart displays monthly precipitation patterns in South New Castle, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In South New Castle, September typically receives around 115 mm (4.5 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec9811110813914113814199115125103103
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in South New Castle

In South New Castle in September, humidity is 77%. With an average temperature of 19°C (66°F), this humidity feels like a heavy blanket wrapping around you, making the air feel thick and sticky, which can be quite uncomfortable for traveling.

September Average Humidity in South New Castle

This chart illustrates the average monthly humidity levels in South New Castle, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in South New Castle is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%88%87%87%81%83%82%76%77%82%89%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in South New Castle

In South New Castle in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in South New Castle.

Maximum UV Index Levels in South New Castle for September

The chart shows the monthly maximum UV Index (UVI) for South New Castle in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in South New Castle typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356910101098642
Data source: South New Castle September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How September Weather in South New Castle Compares to Other Months

Weather in South New Castle varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in South New Castle, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in South New Castle, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-2°C (29°F)98 mm (3.9 inches)88%moderate
February Weather0°C (33°F)111 mm (4.4 inches)88%moderate
March Weather4°C (40°F)108 mm (4.3 inches)87%high
April Weather10°C (50°F)139 mm (5.5 inches)87%very high
May Weather16°C (61°F)141 mm (5.6 inches)81%very high
June Weather20°C (69°F)138 mm (5.4 inches)83%very high
July Weather23°C (74°F)141 mm (5.5 inches)82%very high
August Weather22°C (72°F)99 mm (3.9 inches)76%very high
September Weather19°C (66°F)115 mm (4.5 inches)77%very high
October Weather13°C (56°F)125 mm (4.9 inches)82%high
November Weather5°C (41°F)103 mm (4.0 inches)89%moderate
December Weather1°C (35°F)103 mm (4.0 inches)86%low

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