Last updated: June 24, 2025
In December, the average temperature in Saint Charles, United States hovers around 0°C (32°F). Be prepared for a chilly range, with minimums dropping to -21°C (-5°F) and maximums peaking at 17°C (62°F). Expect about 60 mm (2.4 in) of precipitation spread over 9 days, all while the air maintains a lofty 86% humidity.
In December in Saint Charles, the average temperature is 0°C (32°F). The maximum can reach 17°C (62°F), while the minimum can drop as low as -21°C (-5°F). Travelers should be prepared for a wide range of temperatures, ensuring both warm and warm clothing options are packed.
In Saint Charles in December, the total precipitation amount is 60 mm (2.4 in), occurring over a span of 9 days.
In Saint Charles in December humidity is 86%. With an average temperature of 0°C (32°F), this humidity feels like a biting chill that seeps into your bones, making travel feel uncomfortable and damp, as the cold air combines with the moisture to create a brisk sensation that may deter outdoor exploration.
In Saint Charles 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 Saint Charles, you can visit Hourly UV Index in Saint Charles.
UV Risk Categories
Weather in Saint Charles varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Saint Charles, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -4°C (25°F) | 59 mm (2.3 inches) | 88% | low |
| February Weather | -3°C (26°F) | 63 mm (2.5 inches) | 87% | moderate |
| March Weather | 2°C (36°F) | 61 mm (2.4 inches) | 85% | moderate |
| April Weather | 8°C (46°F) | 88 mm (3.4 inches) | 86% | very high |
| May Weather | 15°C (59°F) | 115 mm (4.5 inches) | 80% | very high |
| June Weather | 21°C (70°F) | 121 mm (4.8 inches) | 80% | very high |
| July Weather | 23°C (75°F) | 66 mm (2.6 inches) | 80% | very high |
| August Weather | 22°C (72°F) | 76 mm (3.0 inches) | 80% | very high |
| September Weather | 18°C (65°F) | 101 mm (4.0 inches) | 80% | high |
| October Weather | 11°C (53°F) | 112 mm (4.4 inches) | 84% | moderate |
| November Weather | 3°C (38°F) | 60 mm (2.4 inches) | 89% | moderate |
| December Weather | 0°C (32°F) | 60 mm (2.4 inches) | 86% | low |