Last updated: June 24, 2025
In Mount Vernon, United States, the average temperature in December hovers around a cool 10°C (51°F). Expect fluctuations, with a minimum of -6°C (22°F) and a maximum of 27°C (80°F). During this month, precipitation totals about 105 mm (4.2 in) spread over 7 days, contributing to an average humidity of 87%. Be prepared for varied weather as you plan your activities!
In December in Mount Vernon, the average temperature is 10°C (51°F). The maximum can reach 27°C (80°F), while the minimum can be as low as -6°C (22°F). This range indicates that travelers should be prepared for both warm days and chilly nights.
In Mount Vernon in December, the total precipitation amount is 105 mm (4.2 in) over the course of 7 days.
In Mount Vernon in December humidity is 87%. With an average temperature of 10°C (51°F), this humidity feels like a heavy blanket enveloping you, making outdoor activities uncomfortable and sticky, and often requiring frequent breaks to stay hydrated and cool.
In Mount Vernon in December, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Mount Vernon for better planning.
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 | 8°C (46°F) | 95 mm (3.8 inches) | 80% | moderate |
| February Weather | 9°C (49°F) | 142 mm (5.6 inches) | 79% | high |
| March Weather | 15°C (59°F) | 132 mm (5.2 inches) | 78% | very high |
| April Weather | 18°C (64°F) | 202 mm (7.9 inches) | 78% | very high |
| May Weather | 23°C (73°F) | 173 mm (6.8 inches) | 81% | extreme |
| June Weather | 27°C (80°F) | 101 mm (4.0 inches) | 78% | extreme |
| July Weather | 29°C (84°F) | 72 mm (2.8 inches) | 73% | extreme |
| August Weather | 28°C (84°F) | 78 mm (3.1 inches) | 66% | extreme |
| September Weather | 26°C (79°F) | 80 mm (3.2 inches) | 65% | very high |
| October Weather | 19°C (67°F) | 137 mm (5.4 inches) | 72% | very high |
| November Weather | 13°C (55°F) | 63 mm (2.5 inches) | 82% | high |
| December Weather | 10°C (51°F) | 105 mm (4.2 inches) | 87% | moderate |