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September Weather in Plainfield, United States

Last updated: June 24, 2025

In September, the average temperature in Plainfield, United States hovers around 17°C (63°F). However, you might experience fluctuations, with a minimum of 1°C (33°F) and maximum highs reaching 33°C (91°F). Prepare for some rain, as 105 mm (4.1 in) of precipitation is likely to fall over about 10 days, accompanied by an average humidity level of 78%.

September Temperature in Plainfield

In September in Plainfield, the average temperature is 17°C (63°F). The maximum can reach 33°C (91°F), while the minimum can dip as low as 1°C (33°F). This climate makes Plainfield a great destination for travelers seeking mild weather, with opportunities for both warm and cool experiences.

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

The chart illustrates September temperature patterns in Plainfield, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Plainfield, September typically has an average temperature of 17°C (63°F), with highs reaching up to 33°C (91°F) and lows dropping to around 1°C (33°F).
JanFebMarAprMayJunJulAugSepOctNovDec191933435769736963493425
Data source: Temperature data for Plainfield 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 Plainfield

In Plainfield in September, the precipitation amount is 105 mm (4.1 in) over the course of 10 days.

September Precipitation Trends in Plainfield

The chart displays monthly precipitation patterns in Plainfield, 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 Plainfield, September typically receives around 105 mm (4.1 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec395262991111091211281051075150
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Plainfield

In Plainfield in September, humidity is 78%. With an average temperature of 17°C (63°F), this humidity feels like a warm, enveloping blanket, making traveling slightly uncomfortable as you navigate the sticky air, prompting the need for frequent breaks in cooler, shaded areas.

September Average Humidity in Plainfield

This chart illustrates the average monthly humidity levels in Plainfield, 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 Plainfield is approximately 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec89%90%87%84%77%75%75%73%78%84%89%87%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Plainfield

In Plainfield 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 Plainfield.

Maximum UV Index Levels in Plainfield for September

The chart shows the monthly maximum UV Index (UVI) for Plainfield 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 Plainfield typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec24589101097532
Data source: Plainfield 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 Plainfield Compares to Other Months

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

This table compares monthly weather conditions in Plainfield, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-7°C (19°F)39 mm (1.5 inches)89%low
February Weather-7°C (20°F)52 mm (2.0 inches)90%moderate
March Weather1°C (33°F)62 mm (2.4 inches)87%moderate
April Weather6°C (43°F)99 mm (3.9 inches)84%very high
May Weather14°C (58°F)111 mm (4.4 inches)77%very high
June Weather20°C (69°F)109 mm (4.3 inches)75%very high
July Weather23°C (73°F)121 mm (4.7 inches)74%very high
August Weather21°C (69°F)128 mm (5.0 inches)73%very high
September Weather17°C (63°F)105 mm (4.1 inches)78%high
October Weather9°C (49°F)107 mm (4.2 inches)84%moderate
November Weather1°C (34°F)51 mm (2.0 inches)89%moderate
December Weather-4°C (26°F)50 mm (2.0 inches)87%low

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