Last updated: June 24, 2025
In December, the average temperature in Mount Vernon, United States hovers around 2°C (35°F). However, temperatures can swing dramatically, with minimums dropping to -17°C (2°F) and maximums reaching up to 17°C (64°F). Expect 97 mm (3.8 in) of precipitation over approximately 12 days, contributing to an average humidity of 86%. Be prepared for a mix of chilly days and wet weather!
In December in Mount Vernon, the average temperature is 2°C (35°F). The maximum can reach 17°C (64°F), while the minimum can drop as low as -17°C (2°F). Be prepared for a wide range of temperatures if you're planning to travel during this time.
In Mount Vernon in December, the precipitation amount is 97 mm (3.8 in) spread over 12 days.
In Mount Vernon in December humidity is 86%. With an average temperature of 2°C (35°F), this humidity feels like a damp chill that seeps into your bones, making traveling quite uncomfortable as your clothes cling to you and the cold air cuts through any warmth you try to find.
In Mount Vernon in December, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Mount Vernon, you can visit 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 December’s weather to other months in Mount Vernon, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -1°C (30°F) | 83 mm (3.3 inches) | 88% | moderate |
| February Weather | 0°C (33°F) | 102 mm (4.0 inches) | 87% | moderate |
| March Weather | 5°C (41°F) | 108 mm (4.2 inches) | 87% | high |
| April Weather | 10°C (51°F) | 130 mm (5.1 inches) | 87% | very high |
| May Weather | 17°C (63°F) | 124 mm (4.9 inches) | 81% | very high |
| June Weather | 22°C (71°F) | 140 mm (5.5 inches) | 82% | very high |
| July Weather | 24°C (75°F) | 115 mm (4.5 inches) | 81% | very high |
| August Weather | 22°C (73°F) | 83 mm (3.3 inches) | 78% | very high |
| September Weather | 20°C (68°F) | 83 mm (3.3 inches) | 78% | very high |
| October Weather | 14°C (57°F) | 100 mm (4.0 inches) | 82% | high |
| November Weather | 5°C (41°F) | 96 mm (3.8 inches) | 89% | moderate |
| December Weather | 2°C (35°F) | 97 mm (3.8 inches) | 86% | low |