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September Weather in New Castle, United States

Last updated: June 24, 2025

In September, the average temperature in New Castle, United States is a pleasant 16°C (60°F). Expect a range of temperatures, with minimums dipping to -2°C (29°F) and maximums reaching up to 32°C (90°F). During this time, anticipate about 18 mm (0.7 in) of precipitation spread over 4 days, accompanied by an average humidity level of 53%.

September Temperature in New Castle

In September in New Castle, the average temperature is 16°C (60°F). Maximums can reach 32°C (90°F), while minimums can drop to as low as -2°C (29°F). Travelers should be prepared for a wide range of temperatures during this time.

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

The chart illustrates September temperature patterns in 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 New Castle, September typically has an average temperature of 16°C (60°F), with highs reaching up to 32°C (90°F) and lows dropping to around -2°C (29°F).
JanFebMarAprMayJunJulAugSepOctNovDec212533395063706860433121
Data source: Temperature data for 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 New Castle

In New Castle in September, the total precipitation amount is 18 mm (0.7 in) spread over a duration of 4 days.

September Precipitation Trends in New Castle

The chart displays monthly precipitation patterns in 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 New Castle, September typically receives around 18 mm (0.7 inches) of precipitation spread over approximately 4 days.
JanFebMarAprMayJunJulAugSepOctNovDec557361484418131318604055
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in New Castle

In New Castle in September, humidity is 53%. With an average temperature of 16°C (60°F), this humidity feels like a comfortable embrace, making it perfect for exploring the sights without feeling overly warm or sticky.

September Average Humidity in New Castle

This chart illustrates the average monthly humidity levels in 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 New Castle is approximately 53%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec90%89%81%74%58%47%39%39%53%72%84%90%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in New Castle

In New Castle in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in New Castle.

Maximum UV Index Levels in New Castle for September

The chart shows the monthly maximum UV Index (UVI) for 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 New Castle typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec469121213121210754
Data source: 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 New Castle Compares to Other Months

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

This table compares monthly weather conditions in New Castle, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-6°C (22°F)55 mm (2.2 inches)90%moderate
February Weather-4°C (25°F)73 mm (2.9 inches)89%high
March Weather1°C (33°F)61 mm (2.4 inches)81%very high
April Weather4°C (39°F)48 mm (1.9 inches)74%extreme
May Weather10°C (50°F)43 mm (1.7 inches)58%extreme
June Weather17°C (63°F)18 mm (0.7 inches)47%extreme
July Weather21°C (70°F)13 mm (0.5 inches)39%extreme
August Weather20°C (68°F)13 mm (0.5 inches)39%extreme
September Weather16°C (60°F)18 mm (0.7 inches)53%very high
October Weather6°C (43°F)60 mm (2.4 inches)72%high
November Weather0°C (32°F)39 mm (1.6 inches)84%moderate
December Weather-6°C (22°F)55 mm (2.2 inches)90%moderate

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