Last updated: June 24, 2025
In December, the average temperature in Montreal, United States hovers around -6°C (22°F), but don't be surprised by the extremes—minimums can plummet to -28°C (-18°F), while maximums may reach up to 14°C (57°F). Expect a fair amount of precipitation, with 74 mm (2.9 in) spread over approximately 12 days, and with an average humidity level of 91%, it’s definitely a month where you’ll want to bundle up!
In December in Montreal, the average temperature is -6°C (22°F). The maximum can reach 14°C (57°F) and the minimum can be as low as -28°C (-18°F). Be sure to pack plenty of warm clothing if you're planning to visit during this time.
In Montreal in December, the precipitation amount is 74 mm (2.9 in) over a span of 12 days.
In Montreal in December humidity is 91%. With an average temperature of -6°C (22°F), this humidity feels like a biting chill that seeps into your bones, making outdoor activities uncomfortable and travel challenging as the air feels dense and heavy, potentially making it more difficult to breathe and leaving a frosty mist on your skin.
In Montreal 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 Montreal, you can visit Hourly UV Index in Montreal.
UV Risk Categories
Weather in Montreal varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Montreal, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -9°C (16°F) | 39 mm (1.5 inches) | 93% | low |
| February Weather | -9°C (16°F) | 52 mm (2.1 inches) | 93% | moderate |
| March Weather | -2°C (28°F) | 52 mm (2.0 inches) | 89% | moderate |
| April Weather | 3°C (38°F) | 87 mm (3.4 inches) | 85% | very high |
| May Weather | 12°C (54°F) | 87 mm (3.4 inches) | 76% | very high |
| June Weather | 18°C (65°F) | 111 mm (4.4 inches) | 71% | very high |
| July Weather | 21°C (70°F) | 87 mm (3.4 inches) | 70% | very high |
| August Weather | 19°C (67°F) | 110 mm (4.3 inches) | 71% | very high |
| September Weather | 15°C (60°F) | 94 mm (3.7 inches) | 73% | high |
| October Weather | 8°C (46°F) | 112 mm (4.4 inches) | 81% | moderate |
| November Weather | -1°C (31°F) | 61 mm (2.4 inches) | 87% | moderate |
| December Weather | -6°C (22°F) | 74 mm (2.9 inches) | 91% | low |