Last updated: June 24, 2025
In Saint Charles, United States, the average temperature in December hovers around 0°C (32°F). However, be prepared for a range, as temperatures can dip as low as -23°C (-9°F) or soar up to 23°C (73°F). Expect about 36 mm (1.4 in) of precipitation spread over 5 days, with an average humidity level of 83%.
In December in Saint Charles, the average temperature is 0°C (32°F). Maximums can reach 23°C (73°F), and minimums can be as low as -23°C (-9°F). Be prepared for a wide range of temperatures, making it essential to pack both warm and light clothing for your travels.
In Saint Charles in December, the precipitation amount is 36 mm (1.4 in) over the course of 5 days.
In Saint Charles in December, humidity is 83%. With an average temperature of 0°C (32°F), this humidity feels like traveling through a thick mist, making every step heavy and the cold pierce even deeper, causing you to constantly seek shelter or warm beverages to counteract the damp chill.
In Saint Charles in December, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in Saint Charles, you can check the information here.
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 | -5°C (23°F) | 41 mm (1.6 inches) | 78% | moderate |
| February Weather | -4°C (25°F) | 39 mm (1.6 inches) | 80% | moderate |
| March Weather | 5°C (41°F) | 85 mm (3.3 inches) | 77% | high |
| April Weather | 10°C (50°F) | 69 mm (2.7 inches) | 77% | very high |
| May Weather | 17°C (63°F) | 163 mm (6.4 inches) | 77% | very high |
| June Weather | 24°C (75°F) | 117 mm (4.6 inches) | 81% | extreme |
| July Weather | 25°C (78°F) | 69 mm (2.7 inches) | 81% | very high |
| August Weather | 24°C (75°F) | 76 mm (3.0 inches) | 77% | very high |
| September Weather | 20°C (69°F) | 117 mm (4.6 inches) | 73% | very high |
| October Weather | 12°C (53°F) | 134 mm (5.3 inches) | 75% | high |
| November Weather | 4°C (39°F) | 43 mm (1.7 inches) | 85% | moderate |
| December Weather | 0°C (32°F) | 36 mm (1.4 inches) | 83% | moderate |