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September Weather in Greencastle, United States

Last updated: June 24, 2025

In Greencastle, United States, the average temperature in September hovers around 21°C (70°F), with fluctuations ranging from a cool 4°C (40°F) to a warm 35°C (95°F). Expect about 110 mm (4.3 in) of precipitation spread across 9 days, while the average humidity remains around 68%. Enjoy the dynamic weather, perfect for all your adventures!

September Temperature in Greencastle

In September in Greencastle, the average temperature is 21°C (70°F). Maximum temperatures can reach up to 35°C (95°F), while minimum temperatures can drop as low as 4°C (40°F). Be prepared for a range of temperatures, so pack versatile clothing for your trip.

September Weather in Greencastle: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Greencastle, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Greencastle, September typically has an average temperature of 21°C (70°F), with highs reaching up to 35°C (95°F) and lows dropping to around 4°C (40°F).
JanFebMarAprMayJunJulAugSepOctNovDec343744546473787670594438
Data source: Temperature data for Greencastle 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 Greencastle

In Greencastle in September, the precipitation amount is 110 mm (4.3 in) over the course of 9 days.

September Precipitation Trends in Greencastle

The chart displays monthly precipitation patterns in Greencastle, 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 Greencastle, September typically receives around 110 mm (4.3 inches) of precipitation spread over approximately 9 days.
JanFebMarAprMayJunJulAugSepOctNovDec62948810111890124871101058195
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Greencastle

In Greencastle in September humidity is 68%. With an average temperature of 21°C (70°F), this humidity feels like a warm embrace, making the air feel slightly heavy and sticky, which can be quite exhausting for travelers.

September Average Humidity in Greencastle

This chart illustrates the average monthly humidity levels in Greencastle, 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 Greencastle is approximately 68%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%86%86%84%78%79%70%59%68%80%87%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Greencastle

In Greencastle 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 Greencastle.

Maximum UV Index Levels in Greencastle for September

The chart shows the monthly maximum UV Index (UVI) for Greencastle 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 Greencastle typically reaches 8, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec357910101098743
Data source: Greencastle 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 Greencastle Compares to Other Months

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

This table compares monthly weather conditions in Greencastle, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (34°F)62 mm (2.4 inches)86%moderate
February Weather3°C (38°F)94 mm (3.7 inches)86%moderate
March Weather6°C (44°F)88 mm (3.5 inches)86%high
April Weather12°C (54°F)101 mm (4.0 inches)84%very high
May Weather18°C (64°F)118 mm (4.7 inches)78%very high
June Weather23°C (73°F)90 mm (3.5 inches)79%very high
July Weather26°C (79°F)124 mm (4.9 inches)70%very high
August Weather24°C (76°F)87 mm (3.4 inches)59%very high
September Weather21°C (70°F)110 mm (4.3 inches)68%very high
October Weather15°C (60°F)104 mm (4.1 inches)80%high
November Weather7°C (45°F)81 mm (3.2 inches)86%moderate
December Weather3°C (38°F)95 mm (3.7 inches)85%moderate

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