Last updated: June 24, 2025
In September, the average temperature in Mount Vernon, United States hovers around 17°C (62°F), creating a comfortable climate for visitors. Expect a minimum of 1°C (34°F) and a maximum soaring to 31°C (87°F). While you're there, be prepared for some rain, as the area experiences approximately 70 mm (2.7 in) of precipitation over 7 days. With an average humidity of 77%, it's a good idea to stay hydrated and enjoy the lush surroundings!
In September in Mount Vernon, the average temperature is 17°C (62°F), with maximums reaching 31°C (87°F) and minimums dropping as low as 1°C (34°F). This variation in temperature makes Mount Vernon an ideal destination for travelers seeking both warm and cool experiences during their visit.
In Mount Vernon in September, the precipitation amount is 70 mm (2.7 in) over a period of 7 days.
In Mount Vernon in September humidity is 77%. With an average temperature of 17°C (62°F), this humidity feels like a warm embrace, creating a lush, almost tropical atmosphere that can be quite stifling for traveling, making it essential to stay hydrated and take frequent breaks in the shade.
In Mount Vernon 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 Mount Vernon.
UV Risk Categories
Weather in Mount Vernon varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Mount Vernon, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -6°C (21°F) | 83 mm (3.2 inches) | 91% | low |
| February Weather | -5°C (23°F) | 84 mm (3.3 inches) | 89% | moderate |
| March Weather | -1°C (31°F) | 72 mm (2.9 inches) | 85% | moderate |
| April Weather | 6°C (43°F) | 121 mm (4.8 inches) | 84% | very high |
| May Weather | 13°C (55°F) | 83 mm (3.3 inches) | 78% | very high |
| June Weather | 18°C (65°F) | 74 mm (2.9 inches) | 72% | very high |
| July Weather | 21°C (70°F) | 121 mm (4.7 inches) | 75% | very high |
| August Weather | 21°C (69°F) | 82 mm (3.2 inches) | 74% | very high |
| September Weather | 17°C (62°F) | 70 mm (2.7 inches) | 77% | high |
| October Weather | 10°C (50°F) | 127 mm (5.0 inches) | 85% | moderate |
| November Weather | 2°C (36°F) | 110 mm (4.3 inches) | 86% | moderate |
| December Weather | -4°C (26°F) | 113 mm (4.4 inches) | 85% | low |