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September Weather in Bristol, United States

Last updated: June 24, 2025

The average temperature in Bristol, United States during September is a comfortable 21°C (70°F). Expect temperatures to range between a minimum of 6°C (43°F) and a maximum of 33°C (92°F). Be prepared for some rain, as the region typically receives around 80 mm (3.1 in) of precipitation over 8 days. Additionally, the average humidity hovers at about 68%, adding a touch of warmth to the atmosphere.

September Temperature in Bristol

In September in Bristol, the average temperature is 21°C (70°F), with maximums reaching up to 33°C (92°F) and minimums dropping as low as 6°C (43°F). This weather makes Bristol an ideal destination for travelers seeking pleasant temperatures and a variety of outdoor activities.

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 21°C (70°F), with highs reaching up to 33°C (92°F) and lows dropping to around 6°C (43°F).
JanFebMarAprMayJunJulAugSepOctNovDec384449566571757470604642
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 precipitation amount is 80 mm (3.1 in) over a period 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 80 mm (3.1 inches) of precipitation spread over approximately 8 days.
JanFebMarAprMayJunJulAugSepOctNovDec971451241291069671868011078123
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 68%. With an average temperature of 21°C (70°F), this humidity feels like a warm embrace, making the air feel slightly heavy and sticky, which can be quite exhausting for travelers.

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 68%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec87%87%86%84%83%83%79%66%68%78%89%86%
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 reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. 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 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec468101111111010853
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 Weather3°C (39°F)97 mm (3.8 inches)87%moderate
February Weather7°C (44°F)145 mm (5.7 inches)87%high
March Weather9°C (49°F)124 mm (4.9 inches)86%very high
April Weather13°C (56°F)129 mm (5.1 inches)84%very high
May Weather18°C (66°F)106 mm (4.2 inches)83%extreme
June Weather22°C (71°F)96 mm (3.8 inches)83%extreme
July Weather24°C (76°F)71 mm (2.8 inches)79%extreme
August Weather23°C (74°F)86 mm (3.4 inches)66%very high
September Weather21°C (70°F)80 mm (3.1 inches)68%very high
October Weather16°C (60°F)110 mm (4.3 inches)78%very high
November Weather8°C (46°F)78 mm (3.1 inches)89%moderate
December Weather6°C (42°F)123 mm (4.8 inches)86%moderate

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