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September Weather in Deerfield, United States

Last updated: June 24, 2025

In September, the average temperature in Deerfield, United States hovers around 14°C (57°F), offering a mild climate. However, be prepared for some variability, as temperatures can dip to a chilly -5°C (23°F) or rise to a warm 28°C (83°F). With an average precipitation of 74 mm (2.9 in) spread over 10 days, and an average humidity level of 77%, visitors can expect a refreshing yet wet atmosphere during this time.

September Temperature in Deerfield

In September in Deerfield, the average temperature is 14°C (57°F). Maximum can reach 28°C (83°F), and minimum can be as low as -5°C (23°F). This variability makes it essential for travelers to pack accordingly for their visit.

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

The chart illustrates September temperature patterns in Deerfield, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Deerfield, September typically has an average temperature of 14°C (57°F), with highs reaching up to 28°C (83°F) and lows dropping to around -5°C (23°F).
JanFebMarAprMayJunJulAugSepOctNovDec161925385261666457453020
Data source: Temperature data for Deerfield 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 Deerfield

In Deerfield in September, the precipitation amount is 74 mm (2.9 in) spread over a period of 10 days.

September Precipitation Trends in Deerfield

The chart displays monthly precipitation patterns in Deerfield, 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 Deerfield, September typically receives around 74 mm (2.9 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec92928213611112013911274147123112
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Deerfield

In Deerfield in September, humidity is 77%. With an average temperature of 14°C (57°F), this humidity feels like a heavy blanket wrapping around you, making outdoor exploration feel muggy and leaving you craving the shade while you travel.

September Average Humidity in Deerfield

This chart illustrates the average monthly humidity levels in Deerfield, 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 Deerfield is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec91%89%85%84%78%72%75%74%77%85%86%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Deerfield

In Deerfield in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in Deerfield.

Maximum UV Index Levels in Deerfield for September

The chart shows the monthly maximum UV Index (UVI) for Deerfield 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 Deerfield typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2468910997532
Data source: Deerfield 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 Deerfield Compares to Other Months

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

This table compares monthly weather conditions in Deerfield, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-9°C (16°F)91 mm (3.6 inches)91%low
February Weather-7°C (19°F)92 mm (3.6 inches)89%moderate
March Weather-4°C (26°F)82 mm (3.2 inches)85%high
April Weather3°C (39°F)136 mm (5.4 inches)84%very high
May Weather11°C (52°F)110 mm (4.4 inches)78%very high
June Weather16°C (61°F)120 mm (4.7 inches)72%very high
July Weather19°C (66°F)139 mm (5.5 inches)75%very high
August Weather18°C (64°F)112 mm (4.4 inches)74%very high
September Weather14°C (57°F)74 mm (2.9 inches)77%high
October Weather7°C (46°F)146 mm (5.8 inches)85%moderate
November Weather-1°C (31°F)123 mm (4.8 inches)86%moderate
December Weather-6°C (21°F)112 mm (4.4 inches)85%low

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