Last updated: June 24, 2025
In December, the average temperature in Sun Prairie, United States hovers around -2°C (29°F). While chilly, temperatures can dip as low as -28°C (-18°F) or rise to a mild 18°C (64°F). Expect 26 mm (1.0 in) of precipitation spread across 7 days, and stay prepared for a high average humidity of 90%.
In December in Sun Prairie, the average temperature is -2°C (29°F) with maximums reaching up to 18°C (64°F) and minimums dipping as low as -28°C (-18°F). Travelers should be prepared for a wide range of temperatures and dress accordingly.
In Sun Prairie in December, the total precipitation amount is 26 mm (1.0 in) spread over a period of 7 days.
In Sun Prairie in December, humidity is 90%. With an average temperature of -2°C (29°F), this humidity feels like an icy breath enveloping you, making every step outdoors feel even colder and more biting, while also creating a heavy, wet atmosphere that can dampen your spirits for traveling.
In Sun Prairie 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 Sun Prairie, you can visit Hourly UV Index in Sun Prairie.
UV Risk Categories
Weather in Sun Prairie varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Sun Prairie, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -4°C (26°F) | 15 mm (0.6 inches) | 87% | low |
| February Weather | -7°C (19°F) | 39 mm (1.6 inches) | 88% | moderate |
| March Weather | 1°C (34°F) | 25 mm (1.0 inches) | 83% | moderate |
| April Weather | 5°C (42°F) | 59 mm (2.3 inches) | 78% | high |
| May Weather | 12°C (54°F) | 71 mm (2.8 inches) | 76% | very high |
| June Weather | 17°C (64°F) | 77 mm (3.0 inches) | 78% | very high |
| July Weather | 22°C (72°F) | 12 mm (0.5 inches) | 77% | very high |
| August Weather | 21°C (69°F) | 24 mm (0.9 inches) | 71% | very high |
| September Weather | 15°C (59°F) | 38 mm (1.5 inches) | 68% | high |
| October Weather | 7°C (44°F) | 37 mm (1.5 inches) | 72% | moderate |
| November Weather | 2°C (36°F) | 29 mm (1.2 inches) | 84% | moderate |
| December Weather | -2°C (29°F) | 26 mm (1.0 inches) | 90% | low |