Last updated: June 24, 2025
In Mason City, United States, the average temperature in December hovers around 2°C (36°F). Expect a significant range, as temperatures can plummet to a chilly -20°C (-4°F) or rise to a pleasant 21°C (70°F). During this month, you can anticipate approximately 53 mm (2.1 in) of precipitation over 7 days, contributing to the average humidity of 84%. Stay prepared for a mix of weather this time of year!
In December in Mason City, the average temperature is 2°C (36°F). The maximum can reach 21°C (70°F), while the minimum can drop as low as -20°C (-4°F). Travelers should prepare for a wide range of temperatures, ensuring they pack accordingly for both warm and cold conditions.
In Mason City in December, the total precipitation amount is 53 mm (2.1 in) spread over a period of 7 days.
In Mason City in December, humidity is 84%. With an average temperature of 2°C (36°F), this humidity feels like a cold, damp blanket wrapping around you, making outdoor activities less inviting and requiring extra layers to stay comfortable while traveling.
In Mason City 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 Mason City, you can visit Hourly UV Index in Mason City.
UV Risk Categories
Weather in Mason City varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Mason City, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -2°C (28°F) | 66 mm (2.6 inches) | 82% | moderate |
| February Weather | -1°C (31°F) | 67 mm (2.7 inches) | 83% | moderate |
| March Weather | 6°C (43°F) | 123 mm (4.8 inches) | 84% | high |
| April Weather | 11°C (52°F) | 120 mm (4.7 inches) | 85% | very high |
| May Weather | 18°C (65°F) | 156 mm (6.1 inches) | 79% | very high |
| June Weather | 24°C (75°F) | 136 mm (5.4 inches) | 82% | extreme |
| July Weather | 25°C (78°F) | 117 mm (4.6 inches) | 80% | very high |
| August Weather | 24°C (75°F) | 97 mm (3.8 inches) | 81% | very high |
| September Weather | 21°C (71°F) | 68 mm (2.7 inches) | 80% | very high |
| October Weather | 14°C (57°F) | 114 mm (4.5 inches) | 82% | high |
| November Weather | 5°C (42°F) | 63 mm (2.5 inches) | 88% | moderate |
| December Weather | 2°C (36°F) | 53 mm (2.1 inches) | 84% | low |