Last updated: June 24, 2025
In September, the average temperature in New Haven, United States hovers around 20°C (69°F), creating a pleasant climate overall. Expect temperatures to range from a cool 10°C (50°F) to a warm 30°C (87°F). During this month, you can anticipate approximately 108 mm (4.3 in) of precipitation over about 10 days, with an average humidity of 68%. Whether you're planning outdoor adventures or cozy indoor activities, September offers a delightful balance of warmth and refreshment.
In September in New Haven, the average temperature is 20°C (69°F). Maximums can reach 30°C (87°F) and minimums can be as low as 10°C (50°F). This makes it an ideal time for outdoor activities and exploring the area comfortably.
In New Haven in September, the total precipitation amount is 108 mm (4.3 in) spread over a duration of 10 days.
In New Haven in September, humidity is 68%. With an average temperature of 20°C (69°F), this humidity feels like a warm embrace, making outdoor exploration both refreshing and slightly sticky, requiring occasional breaks in the shade to stay comfortable while traveling.
In New Haven 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 New Haven.
UV Risk Categories
Weather in New Haven varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in New Haven, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 1°C (34°F) | 90 mm (3.5 inches) | 84% | moderate |
| February Weather | 1°C (35°F) | 132 mm (5.2 inches) | 82% | moderate |
| March Weather | 4°C (39°F) | 109 mm (4.3 inches) | 81% | high |
| April Weather | 8°C (47°F) | 153 mm (6.0 inches) | 78% | very high |
| May Weather | 14°C (57°F) | 130 mm (5.1 inches) | 69% | very high |
| June Weather | 19°C (67°F) | 93 mm (3.7 inches) | 69% | very high |
| July Weather | 23°C (74°F) | 132 mm (5.2 inches) | 62% | very high |
| August Weather | 23°C (74°F) | 96 mm (3.8 inches) | 65% | very high |
| September Weather | 20°C (69°F) | 108 mm (4.3 inches) | 68% | very high |
| October Weather | 15°C (60°F) | 171 mm (6.7 inches) | 74% | high |
| November Weather | 8°C (47°F) | 112 mm (4.4 inches) | 82% | moderate |
| December Weather | 4°C (39°F) | 160 mm (6.3 inches) | 80% | low |