Climate averages 1991–2020
Rapid City weather
in January.
A cold, very dry month: the coolest and the driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
January is a cold month in Rapid City: daytime highs average 2.5°C and nights cool to about -8.1°C. By daytime temperature it is the coolest month of the year.
Expect about 13 mm of rain on roughly 4 days, which makes January a very dry month (the driest month of the year). Daylight, from sunrise to sunset, lasts about 9 h 17 min on an average January day.
The nearest other city in this atlas is Bismarck (358 km away). In January its highs average -5.9°C, 8.4°C cooler than Rapid City, with 16 mm of precipitation.
Among the 498 cities listed in the United States, Rapid City ranks 384th of 498 for the warmest January highs and joint 4th of 498 for the driest January (rainfall, lowest first). The mean January high of those 498 cities is 9.5°C; Rapid City is 7.0°C cooler than that mean.
From January to February, average highs rise by 1.0°C to 3.5°C, and monthly rainfall rises from 13 mm to 20 mm.
The annual picture
January in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Rapid City climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January, selected | 2.5°C-8.1°C | -8.1°C | 13 | 3.9 | 9.39 h |
| February | 3.5°C-7.6°C | -7.6°C | 20 | 5.1 | 10.410 h |
| March | 8.5°C-3.5°C | -3.5°C | 40 | 7.6 | 11.912 h |
| April | 12.8°C1.1°C | 1.1°C | 80 | 11.8 | 13.413 h |
| May | 18.4°C7.2°C | 7.2°C | 112 | 14.1 | 14.715 h |
| June | 24.4°C12.9°C | 12.9°C | 97 | 14.5 | 15.415 h |
| July | 28.9°C16.9°C | 16.9°C | 78 | 13.4 | 15.115 h |
| August | 28.2°C16.1°C | 16.1°C | 60 | 10.8 | 14.014 h |
| September | 23.3°C11.2°C | 11.2°C | 42 | 6.7 | 12.613 h |
| October | 14.9°C3.9°C | 3.9°C | 50 | 7.3 | 11.011 h |
| November | 7.9°C-2.5°C | -2.5°C | 20 | 4.4 | 9.710 h |
| December | 2.8°C-6.9°C | -6.9°C | 15 | 3.6 | 9.09 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
January in nearby cities
- Bismarck in JanuaryUnited States · 358 kmHigh -5.9°C · Low -15.1°C · 16 mm precipitation
- Fort Collins in JanuaryUnited States · 417 kmHigh 4.6°C · Low -8.2°C · 16 mm rain
- Greeley in JanuaryUnited States · 424 kmHigh 5.4°C · Low -7.4°C · 11 mm rain
- Loveland in JanuaryUnited States · 437 kmHigh 4.5°C · Low -8.9°C · 16 mm rain
- Billings in JanuaryUnited States · 456 kmHigh 1.3°C · Low -8.8°C · 22 mm precipitation
- Longmont in JanuaryUnited States · 462 kmHigh 4.5°C · Low -8.4°C · 19 mm rain
- Boulder in JanuaryUnited States · 482 kmHigh 4.2°C · Low -8.7°C · 24 mm rain
- Thornton in JanuaryUnited States · 490 kmHigh 4.3°C · Low -9.7°C · 22 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Rapid City) is explained once on the Rapid City year overview and on the Sources, method and limits page.