Last updated: June 24, 2025
In December, the average temperature in Iron Mountain, United States hovers around -5°C (23°F), with extremes ranging from a frigid -30°C (-22°F) to a mild 14°C (57°F). Expect approximately 55 mm (2.2 in) of precipitation over 8 days, and prepare for a relatively high humidity level at 87%.
In December in Iron Mountain, the average temperature is -5°C (23°F). The maximum can reach 14°C (57°F), while the minimum can drop as low as -30°C (-22°F). Travelers should be prepared for a wide range of temperatures and pack accordingly for their visit.
In Iron Mountain in December, the precipitation amount is 55 mm (2.2 in) over the course of 8 days.
In Iron Mountain in December humidity is 87%. With an average temperature of -5°C (23°F), this humidity feels like a heavy, damp blanket enveloping you, making even the cold air seem more biting and clammy, which can be quite uncomfortable for traveling.
In Iron Mountain 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 Iron Mountain, you can visit Hourly UV Index in Iron Mountain.
UV Risk Categories
Weather in Iron Mountain varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Iron Mountain, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -8°C (17°F) | 33 mm (1.3 inches) | 89% | low |
| February Weather | -9°C (17°F) | 49 mm (1.9 inches) | 90% | moderate |
| March Weather | -2°C (28°F) | 48 mm (1.9 inches) | 87% | moderate |
| April Weather | 4°C (39°F) | 90 mm (3.5 inches) | 84% | high |
| May Weather | 12°C (55°F) | 85 mm (3.3 inches) | 77% | very high |
| June Weather | 18°C (65°F) | 108 mm (4.3 inches) | 75% | very high |
| July Weather | 21°C (70°F) | 103 mm (4.1 inches) | 74% | very high |
| August Weather | 19°C (67°F) | 118 mm (4.6 inches) | 73% | very high |
| September Weather | 15°C (60°F) | 90 mm (3.5 inches) | 78% | high |
| October Weather | 8°C (46°F) | 99 mm (3.9 inches) | 84% | moderate |
| November Weather | 0°C (32°F) | 51 mm (2.0 inches) | 89% | moderate |
| December Weather | -5°C (23°F) | 55 mm (2.2 inches) | 87% | low |