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September Weather in Chelsea, United States

Last updated: June 24, 2025

The average temperature in Chelsea, United States during September is a comfortable 24°C (76°F). However, be prepared for temperature fluctuations, as it can drop to a cool 8°C (47°F) and rise to a warm 35°C (96°F). Expect some rain, with a total precipitation of 91 mm (3.6 in) over 7 days, while the average humidity sits at 67%. Stay ready for a mix of weather this month!

September Temperature in Chelsea

In September in Chelsea, the average temperature is 24°C (76°F). Maximum temperatures can reach 35°C (96°F), while minimums can drop as low as 8°C (47°F). This makes it an ideal time to explore Chelsea, offering warm days and cooler evenings for comfortable travel adventures.

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

The chart illustrates September temperature patterns in Chelsea, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Chelsea, September typically has an average temperature of 24°C (76°F), with highs reaching up to 35°C (96°F) and lows dropping to around 8°C (47°F).
JanFebMarAprMayJunJulAugSepOctNovDec384053596979828076625044
Data source: Temperature data for Chelsea 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 Chelsea

In Chelsea in September, the precipitation amount is 91 mm (3.6 in) over a span of 7 days.

September Precipitation Trends in Chelsea

The chart displays monthly precipitation patterns in Chelsea, 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 Chelsea, September typically receives around 91 mm (3.6 inches) of precipitation spread over approximately 7 days.
JanFebMarAprMayJunJulAugSepOctNovDec766812213920410397113911395350
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Chelsea

In Chelsea in September humidity is 67%. With an average temperature of 24°C (76°F), this humidity feels like a warm, steamy embrace, making travel slightly more challenging as you navigate through the thick air.

September Average Humidity in Chelsea

This chart illustrates the average monthly humidity levels in Chelsea, 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 Chelsea is approximately 67%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec77%76%71%74%83%83%81%73%67%72%82%85%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Chelsea

In Chelsea 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 Chelsea.

Maximum UV Index Levels in Chelsea for September

The chart shows the monthly maximum UV Index (UVI) for Chelsea 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 Chelsea typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec36710101111109753
Data source: Chelsea 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 Chelsea Compares to Other Months

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

This table compares monthly weather conditions in Chelsea, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather3°C (38°F)76 mm (3.0 inches)77%moderate
February Weather5°C (41°F)68 mm (2.7 inches)76%high
March Weather12°C (53°F)122 mm (4.8 inches)71%high
April Weather15°C (59°F)139 mm (5.5 inches)73%very high
May Weather21°C (69°F)204 mm (8.0 inches)83%very high
June Weather26°C (79°F)103 mm (4.1 inches)83%extreme
July Weather28°C (82°F)97 mm (3.8 inches)81%extreme
August Weather27°C (80°F)113 mm (4.4 inches)73%very high
September Weather24°C (76°F)91 mm (3.6 inches)67%very high
October Weather16°C (62°F)139 mm (5.5 inches)72%high
November Weather10°C (50°F)53 mm (2.1 inches)82%moderate
December Weather7°C (44°F)50 mm (2.0 inches)85%moderate

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