Last updated: June 24, 2025
In January, the average temperature in Rapid City, United States hovers around -6°C (22°F). While the minimum can dip to a chilling -28°C (-18°F), temperatures can occasionally peak at a comfortable 11°C (53°F). Expect about 57 mm (2.2 in) of precipitation spread over 12 days, accompanied by a high average humidity of 91%, creating a notably brisk and damp atmosphere.
In January in Rapid City, the average temperature is -6°C (22°F). Maximums can reach 11°C (53°F) and minimums can be as low as -28°C (-18°F). Travelers should be prepared for a wide range of temperatures and ensure they have suitable clothing for both chilly and milder conditions.
In Rapid City in January, the precipitation amount is 57 mm (2.2 in) over a span of 12 days.
In Rapid City in January humidity is 91%. With an average temperature of -6°C (22°F), this humidity feels like a biting chill that seeps into your bones, making outdoor activities uncomfortable and travel challenging as the air feels dense and heavy, potentially making it more difficult to breathe and leaving a frosty mist on your skin.
In Rapid City in January, 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 Rapid City, you can visit Hourly UV Index in Rapid City.
UV Risk Categories
Weather in Rapid City varies notably across the year, with each month offering distinct climate conditions. This page compares January’s weather to other months in Rapid City, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -6°C (22°F) | 57 mm (2.2 inches) | 91% | low |
| February Weather | -6°C (22°F) | 62 mm (2.4 inches) | 91% | moderate |
| March Weather | -1°C (31°F) | 62 mm (2.4 inches) | 87% | moderate |
| April Weather | 5°C (42°F) | 97 mm (3.8 inches) | 87% | high |
| May Weather | 13°C (56°F) | 119 mm (4.7 inches) | 82% | very high |
| June Weather | 19°C (66°F) | 111 mm (4.4 inches) | 79% | very high |
| July Weather | 21°C (71°F) | 103 mm (4.1 inches) | 75% | very high |
| August Weather | 20°C (68°F) | 91 mm (3.6 inches) | 76% | very high |
| September Weather | 16°C (61°F) | 78 mm (3.1 inches) | 79% | high |
| October Weather | 10°C (49°F) | 131 mm (5.2 inches) | 83% | moderate |
| November Weather | 2°C (35°F) | 77 mm (3.0 inches) | 86% | moderate |
| December Weather | -2°C (28°F) | 74 mm (2.9 inches) | 87% | low |