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September Weather in Chester, United States

Last updated: June 24, 2025

In Chester, United States, the average temperature in September is a comfortable 16°C (61°F). However, prepare for a range as the minimum can drop to -3°C (28°F) while the maximum may soar to 35°C (95°F). Expect a total precipitation of 27 mm (1.1 in) over about 4 days, with an average humidity of 46% to round out the climate experience.

September Temperature in Chester

In September in Chester, the average temperature is 16°C (61°F). Maximum temperatures can reach up to 35°C (95°F), while minimums can drop as low as -3°C (28°F). This variation in temperature makes it essential to pack for both warm and chilly conditions, ensuring you’re prepared for any weather while exploring the area.

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

The chart illustrates September temperature patterns in Chester, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Chester, September typically has an average temperature of 16°C (61°F), with highs reaching up to 35°C (95°F) and lows dropping to around -3°C (28°F).
JanFebMarAprMayJunJulAugSepOctNovDec323235415162716961483931
Data source: Temperature data for Chester 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 Chester

In Chester in September, the total precipitation amount is 27 mm (1.1 in) over a span of 4 days.

September Precipitation Trends in Chester

The chart displays monthly precipitation patterns in Chester, 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 Chester, September typically receives around 27 mm (1.1 inches) of precipitation spread over approximately 4 days.
JanFebMarAprMayJunJulAugSepOctNovDec21723219810075229172853106171
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Chester

In Chester in September, humidity is 46%. With an average temperature of 16°C (61°F), this humidity feels like a refreshing, mildly cool environment for traveling, where the air is crisp enough to keep you comfortable while exploring the sights without feeling stifling or oppressive.

September Average Humidity in Chester

This chart illustrates the average monthly humidity levels in Chester, 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 Chester is approximately 46%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec86%87%86%83%72%67%56%42%46%67%86%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Chester

In Chester 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 Chester.

Maximum UV Index Levels in Chester for September

The chart shows the monthly maximum UV Index (UVI) for Chester 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 Chester typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec45810121211119753
Data source: Chester 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 Chester Compares to Other Months

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

This table compares monthly weather conditions in Chester, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather0°C (32°F)217 mm (8.5 inches)86%moderate
February Weather0°C (32°F)232 mm (9.1 inches)87%moderate
March Weather2°C (35°F)198 mm (7.8 inches)86%very high
April Weather5°C (42°F)100 mm (3.9 inches)83%very high
May Weather11°C (52°F)75 mm (3.0 inches)72%extreme
June Weather17°C (63°F)22 mm (0.9 inches)67%extreme
July Weather22°C (71°F)9 mm (0.3 inches)56%extreme
August Weather21°C (69°F)16 mm (0.6 inches)42%extreme
September Weather16°C (61°F)27 mm (1.1 inches)46%very high
October Weather9°C (49°F)53 mm (2.1 inches)67%high
November Weather4°C (39°F)106 mm (4.2 inches)86%moderate
December Weather-1°C (31°F)171 mm (6.7 inches)86%moderate

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