Last updated: June 24, 2025
In December, the average temperature in Saint Louis, United States hovers around -1°C (31°F). Expect chilly conditions with minimums dipping to -26°C (-14°F), while the mercury can rise to a maximum of 16°C (62°F). Precipitation averages 63 mm (2.5 in) over 9 days, contributing to an average humidity of 86%. 🌧️❄️
In December in Saint Louis, the average temperature is -1°C (31°F). Maximum temperatures can reach 16°C (62°F), while minimums can dip as low as -26°C (-14°F). Travelers should be prepared for a wide range of temperatures and pack accordingly for both mild and extreme cold conditions.
In Saint Louis in December, the total precipitation amount is 63 mm (2.5 in) spread over a duration of 9 days.
In Saint Louis in December humidity is 86%. With an average temperature of -1°C (31°F), this humidity feels like an eerie chill enveloping you, making travel uncomfortable as the damp air bites into your skin and the cold seeps through even the warmest of clothes, creating an atmosphere that is heavy and uninviting.
In Saint Louis 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 Louis, you can visit Hourly UV Index in Saint Louis.
UV Risk Categories
Weather in Saint Louis varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Saint Louis, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -4°C (24°F) | 55 mm (2.2 inches) | 88% | low |
| February Weather | -4°C (25°F) | 59 mm (2.3 inches) | 87% | moderate |
| March Weather | 2°C (35°F) | 58 mm (2.3 inches) | 85% | moderate |
| April Weather | 7°C (46°F) | 86 mm (3.4 inches) | 86% | very high |
| May Weather | 15°C (59°F) | 115 mm (4.5 inches) | 80% | very high |
| June Weather | 20°C (69°F) | 113 mm (4.5 inches) | 80% | very high |
| July Weather | 23°C (74°F) | 67 mm (2.7 inches) | 80% | very high |
| August Weather | 22°C (71°F) | 81 mm (3.2 inches) | 80% | very high |
| September Weather | 18°C (64°F) | 98 mm (3.9 inches) | 80% | high |
| October Weather | 11°C (52°F) | 120 mm (4.7 inches) | 84% | moderate |
| November Weather | 3°C (38°F) | 57 mm (2.2 inches) | 89% | moderate |
| December Weather | -1°C (31°F) | 63 mm (2.5 inches) | 86% | low |