Last updated: June 24, 2025
In December, the average temperature in Glen Ullin, United States hovers around -5°C (23°F), with a minimum dipping to -29°C (-20°F) and a maximum reaching 17°C (63°F). You'll experience about 20 mm (0.8 in) of precipitation over approximately 4 days, while the air will feel quite humid, averaging around 84%.
In December in Glen Ullin, the average temperature is -5°C (23°F). The maximum can reach 17°C (63°F), while the minimum can drop as low as -29°C (-20°F). Travelers should be prepared for a wide range of temperatures, from chilly days to surprisingly warm afternoons.
In Glen Ullin in December, the total precipitation amount is 20 mm (0.8 in) spread over a period of 4 days.
In Glen Ullin in December, humidity is 84%. With an average temperature of -5°C (23°F), this humidity feels like an icy blanket wrapping around you, making the cold air bite even deeper and turning travel into a brisk, challenging adventure where each breath comes with a frosty reminder of the chill.
In Glen Ullin 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 Glen Ullin, you can visit Hourly UV Index in Glen Ullin.
UV Risk Categories
Weather in Glen Ullin varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Glen Ullin, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -8°C (17°F) | 12 mm (0.5 inches) | 84% | low |
| February Weather | -10°C (14°F) | 16 mm (0.6 inches) | 88% | moderate |
| March Weather | -1°C (31°F) | 25 mm (1.0 inches) | 78% | moderate |
| April Weather | 4°C (40°F) | 28 mm (1.1 inches) | 75% | very high |
| May Weather | 13°C (55°F) | 61 mm (2.4 inches) | 76% | very high |
| June Weather | 20°C (68°F) | 54 mm (2.1 inches) | 79% | very high |
| July Weather | 23°C (73°F) | 61 mm (2.4 inches) | 78% | very high |
| August Weather | 21°C (70°F) | 72 mm (2.8 inches) | 78% | very high |
| September Weather | 16°C (60°F) | 51 mm (2.0 inches) | 69% | high |
| October Weather | 6°C (43°F) | 51 mm (2.0 inches) | 71% | moderate |
| November Weather | -1°C (31°F) | 17 mm (0.7 inches) | 82% | moderate |
| December Weather | -5°C (23°F) | 20 mm (0.8 inches) | 84% | low |