Last updated: June 24, 2025
In Gillette, United States, the average temperature in December is a brisk -1°C (30°F). While temperatures can dip as low as -23°C (-9°F), they can occasionally soar to a pleasant 21°C (71°F). Expect about 24 mm (0.9 in) of precipitation spread over 6 days, contributing to an average humidity of 81%. Prepare accordingly for a mix of chilly air and occasional wet days!
In December in Gillette, the average temperature is -1°C (30°F), with maximums reaching 21°C (71°F) and minimums dropping as low as -23°C (-9°F). It's a month of significant temperature fluctuations, so travelers should be prepared for both chilly days and surprisingly warm spells.
In Gillette in December, the total precipitation amount is 24 mm (0.9 in) over a span of 6 days.
In Gillette in December, humidity is 81%. With an average temperature of -1°C (30°F), this humidity feels like an extra layer of chill settles in, making travel uncomfortable and the cold air cling to your skin, dampening the experience with every breath.
In Gillette 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 Gillette, you can visit Hourly UV Index in Gillette.
UV Risk Categories
Weather in Gillette varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in Gillette, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -3°C (27°F) | 19 mm (0.8 inches) | 78% | moderate |
| February Weather | -5°C (23°F) | 26 mm (1.0 inches) | 79% | moderate |
| March Weather | 3°C (38°F) | 33 mm (1.3 inches) | 71% | high |
| April Weather | 6°C (42°F) | 61 mm (2.4 inches) | 70% | very high |
| May Weather | 12°C (53°F) | 67 mm (2.6 inches) | 75% | very high |
| June Weather | 19°C (67°F) | 39 mm (1.6 inches) | 82% | extreme |
| July Weather | 23°C (74°F) | 56 mm (2.2 inches) | 84% | extreme |
| August Weather | 21°C (71°F) | 35 mm (1.4 inches) | 85% | very high |
| September Weather | 16°C (62°F) | 43 mm (1.7 inches) | 79% | very high |
| October Weather | 6°C (44°F) | 47 mm (1.9 inches) | 75% | moderate |
| November Weather | 3°C (37°F) | 20 mm (0.8 inches) | 75% | moderate |
| December Weather | -1°C (30°F) | 24 mm (0.9 inches) | 81% | low |