September Weather in Bristol, United States

Last updated: June 24, 2025

In September, the average temperature in Bristol, United States hovers around 26°C (79°F), creating a warm and inviting atmosphere. Expect a minimum temperature of 14°C (57°F), while highs can reach up to 38°C (100°F). With 152 mm (6.0 in) of precipitation spread over 14 days, it’s wise to be prepared for occasional rain. Additionally, the average humidity sits at a comfortable 79%, adding to the tropical feel of the month.

September Temperature in Bristol

In September in Bristol, the average temperature is 26°C (79°F), with maximums reaching up to 38°C (100°F) and minimums dropping as low as 14°C (57°F). This diverse temperature range makes it an ideal time for travelers to enjoy both warm days and cooler evenings.

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 26°C (79°F), with highs reaching up to 38°C (100°F) and lows dropping to around 14°C (57°F).

Data source: Temperature data for Bristol generated using information from the Copernicus Climate Change Service.

September Precipitation in Bristol

In Bristol in September, the precipitation amount is 152 mm (6.0 in) over a span of 14 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 152 mm (6.0 inches) of precipitation spread over approximately 14 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

September Humidity in Bristol

In Bristol in September humidity is 79%. With an average temperature of 26°C (79°F), this humidity feels like a warm, sticky embrace that can make outdoor activities feel exhausting. Travelers should be prepared for a heavy air that clings to the skin, making hydration essential while navigating the sights and sounds of the city.

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 79%, offering insight into how humid the weather typically is during this month.

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.

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.
	Temperature	Precipitation	Humidity	UV
January Weather	12°C (54°F)	84 mm (3.3 inches)	83%	moderate
February Weather	15°C (60°F)	122 mm (4.8 inches)	82%	very high
March Weather	17°C (64°F)	57 mm (2.2 inches)	79%	very high
April Weather	20°C (68°F)	107 mm (4.2 inches)	77%	very high
May Weather	24°C (75°F)	103 mm (4.1 inches)	74%	extreme
June Weather	26°C (80°F)	181 mm (7.1 inches)	70%	extreme
July Weather	27°C (81°F)	173 mm (6.8 inches)	78%	extreme
August Weather	27°C (81°F)	191 mm (7.5 inches)	78%	extreme
September Weather	26°C (79°F)	152 mm (6.0 inches)	79%	very high
October Weather	23°C (73°F)	100 mm (3.9 inches)	74%	very high
November Weather	16°C (60°F)	46 mm (1.8 inches)	83%	high
December Weather	13°C (56°F)	126 mm (5.0 inches)	86%	moderate