Last updated: June 24, 2025
In September, the average temperature in Chelsea, United States hovers around 15°C (60°F). Be prepared for chilly nights, as temperatures can drop to a minimum of -4°C (25°F), while daytime highs can reach up to 31°C (88°F). Expect about 71 mm (2.8 in) of precipitation over 8 days, accompanied by an average humidity of 72%.
In September in Chelsea, the average temperature is 15°C (60°F). The maximum can reach 31°C (88°F) and the minimum can be as low as -4°C (25°F). Travelers should be prepared for a wide range of temperatures during this time, ensuring they pack accordingly for both warm and cool weather.
In Chelsea in September, the precipitation amount is 71 mm (2.8 in) over the course of 8 days.
In Chelsea in September humidity is 72%. With an average temperature of 15°C (60°F), this humidity feels like a warm embrace, creating a slightly muggy atmosphere that can make strolling around a bit sticky. Travelers might find themselves longing for a refreshing breeze, and it’s advisable to stay hydrated while exploring local sights.
In Chelsea 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 Chelsea.
UV Risk Categories
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.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -7°C (19°F) | 77 mm (3.0 inches) | 89% | low |
| February Weather | -6°C (22°F) | 80 mm (3.2 inches) | 88% | moderate |
| March Weather | -2°C (29°F) | 71 mm (2.8 inches) | 86% | moderate |
| April Weather | 5°C (42°F) | 117 mm (4.6 inches) | 84% | very high |
| May Weather | 12°C (55°F) | 96 mm (3.8 inches) | 76% | very high |
| June Weather | 17°C (64°F) | 97 mm (3.8 inches) | 72% | very high |
| July Weather | 20°C (69°F) | 140 mm (5.5 inches) | 66% | very high |
| August Weather | 19°C (67°F) | 98 mm (3.9 inches) | 64% | very high |
| September Weather | 15°C (60°F) | 71 mm (2.8 inches) | 72% | high |
| October Weather | 9°C (48°F) | 141 mm (5.6 inches) | 81% | moderate |
| November Weather | 1°C (33°F) | 104 mm (4.1 inches) | 87% | moderate |
| December Weather | -5°C (24°F) | 88 mm (3.4 inches) | 84% | low |