Last updated: June 24, 2025
In September, the average temperature in Bristol, United States hovers around 19°C (67°F), making it quite pleasant. However, be prepared for a range, as temperatures can drop to a chilly 3°C (38°F) or soar to a warm 33°C (92°F). Expect about 80 mm (3.1 in) of precipitation over 9 days, with an average humidity of 78%. Whether you're exploring the outdoors or enjoying indoor activities, this month's climate promises a bit of everything!
In September in Bristol, the average temperature is 19°C (67°F). Maximum temperatures can reach 33°C (92°F), while minimums can dip as low as 3°C (38°F). It's a good idea to pack layers and be prepared for both warm days and chilly nights while traveling.
In Bristol in September, the precipitation amount is 80 mm (3.1 in) spread over 9 days.
In Bristol in September humidity is 78%. With an average temperature of 19°C (67°F), this humidity feels like a warm, heavy blanket enveloping you, making traveling feel both sticky and sluggish as you navigate through the day.
In Bristol in September, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Bristol.
UV Risk Categories
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.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -3°C (27°F) | 72 mm (2.8 inches) | 85% | moderate |
| February Weather | -2°C (29°F) | 77 mm (3.0 inches) | 85% | moderate |
| March Weather | 4°C (39°F) | 99 mm (3.9 inches) | 86% | high |
| April Weather | 9°C (48°F) | 100 mm (3.9 inches) | 87% | very high |
| May Weather | 16°C (61°F) | 142 mm (5.6 inches) | 81% | very high |
| June Weather | 22°C (72°F) | 128 mm (5.1 inches) | 82% | very high |
| July Weather | 24°C (75°F) | 121 mm (4.7 inches) | 81% | very high |
| August Weather | 22°C (72°F) | 103 mm (4.1 inches) | 79% | very high |
| September Weather | 19°C (67°F) | 80 mm (3.1 inches) | 78% | very high |
| October Weather | 13°C (55°F) | 129 mm (5.1 inches) | 81% | high |
| November Weather | 4°C (40°F) | 80 mm (3.1 inches) | 89% | moderate |
| December Weather | 1°C (34°F) | 61 mm (2.4 inches) | 86% | moderate |