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September Weather in Deerfield, United States

Last updated: June 24, 2025

In Deerfield, United States, the average temperature in September hovers around 22°C (71°F). However, temperatures can vary significantly, with a minimum of 3°C (37°F) and a potential peak of 38°C (101°F). Expect about 42 mm (1.7 in) of precipitation spread across 4 days, accompanied by an average humidity level of 79%.

September Temperature in Deerfield

In September in Deerfield, the average temperature is 22°C (71°F). Maximums can reach 38°C (101°F), while minimums can drop as low as 3°C (37°F). This variation makes it essential for travelers to pack a range of clothing options to stay comfortable.

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 22°C (71°F), with highs reaching up to 38°C (101°F) and lows dropping to around 3°C (37°F).
JanFebMarAprMayJunJulAugSepOctNovDec333446536376797671554537
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 42 mm (1.7 in) distributed over a span of 4 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 42 mm (1.7 inches) of precipitation spread over approximately 4 days.
JanFebMarAprMayJunJulAugSepOctNovDec1617474111250466742391018
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 79%. With an average temperature of 22°C (71°F), this humidity feels like a warm, sticky embrace that can make any outdoor adventure quite challenging for traveling; it's advisable to stay hydrated and take breaks in the shade to fully enjoy the sights.

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 79%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec74%77%65%67%81%82%82%84%79%75%79%83%
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 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For 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 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec45710111212119753
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 Weather1°C (33°F)16 mm (0.6 inches)74%moderate
February Weather1°C (34°F)17 mm (0.7 inches)77%moderate
March Weather8°C (46°F)47 mm (1.9 inches)65%high
April Weather12°C (54°F)41 mm (1.6 inches)67%very high
May Weather17°C (63°F)112 mm (4.4 inches)81%extreme
June Weather24°C (76°F)50 mm (2.0 inches)82%extreme
July Weather26°C (79°F)46 mm (1.8 inches)82%extreme
August Weather25°C (77°F)67 mm (2.6 inches)84%extreme
September Weather22°C (71°F)42 mm (1.7 inches)79%very high
October Weather13°C (55°F)39 mm (1.6 inches)75%high
November Weather7°C (45°F)10 mm (0.4 inches)79%moderate
December Weather3°C (37°F)18 mm (0.7 inches)83%moderate

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