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September Weather in Bristol, United States

Last updated: June 24, 2025

In September, the average temperature in Bristol, United States hovers around 16°C (61°F). This month can bring temperature extremes, with lows dipping to -2°C (28°F) and highs soaring to 32°C (89°F). Expect around 67 mm (2.6 in) of precipitation over approximately 8 days, and a notable average humidity level of 78%.

September Temperature in Bristol

In September, in Bristol, the average temperature is 16°C (61°F). The maximum can reach 32°C (89°F), while the minimum can be as low as -2°C (28°F). Be prepared for a wide range of temperatures if you're planning to travel during this time.

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

The chart illustrates September temperature patterns in Bristol, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Bristol, September typically has an average temperature of 16°C (61°F), with highs reaching up to 32°C (89°F) and lows dropping to around -2°C (28°F).
JanFebMarAprMayJunJulAugSepOctNovDec202330435665706861503526
Data source: Temperature data for Bristol 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 Bristol

In Bristol in September, the total precipitation amount is 67 mm (2.6 in) over the course of 8 days.

September Precipitation Trends in Bristol

The chart displays monthly precipitation patterns in Bristol, 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 Bristol, September typically receives around 67 mm (2.6 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec7979731099299110926714210479
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Bristol

In Bristol in September, humidity is 78%. With an average temperature of 16°C (61°F), this humidity feels like a warm, sticky embrace, making travel somewhat uncomfortable as it clings to your skin and creates a heavy atmosphere that can drain your energy.

September Average Humidity in Bristol

This chart illustrates the average monthly humidity levels in Bristol, 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 Bristol is approximately 78%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec93%92%86%85%80%74%76%75%78%86%89%89%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Bristol

In Bristol 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 Bristol.

Maximum UV Index Levels in Bristol for September

The chart shows the monthly maximum UV Index (UVI) for Bristol 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 Bristol typically reaches 7, which falls under the high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec2458910997532
Data source: Bristol 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 Bristol Compares to Other Months

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

This table compares monthly weather conditions in Bristol, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-7°C (20°F)79 mm (3.1 inches)93%low
February Weather-5°C (23°F)79 mm (3.1 inches)92%moderate
March Weather-1°C (31°F)73 mm (2.9 inches)86%moderate
April Weather6°C (43°F)108 mm (4.3 inches)85%very high
May Weather13°C (56°F)92 mm (3.6 inches)80%very high
June Weather18°C (65°F)99 mm (3.9 inches)74%very high
July Weather21°C (70°F)110 mm (4.3 inches)76%very high
August Weather20°C (69°F)92 mm (3.6 inches)75%very high
September Weather16°C (61°F)67 mm (2.6 inches)78%high
October Weather10°C (50°F)142 mm (5.6 inches)86%moderate
November Weather2°C (35°F)103 mm (4.1 inches)88%moderate
December Weather-3°C (26°F)79 mm (3.1 inches)89%low

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