South Dakota climate by month
January highs across South Dakota range from 24°F in Aberdeen to 36°F in Rapid City; July highs from 79°F in Keystone to 86°F in Rapid City. The most common best months across these cities are May, June.
South Dakota weather month by month
Average of the 4 South Dakota cities on this site, computed from NOAA's unrounded values (so it can differ by a degree from averaging the rounded city figures); individual cities differ, sometimes a lot.
| Month | High | Low | Wet days | Snow |
|---|---|---|---|---|
| January | 31°F | 9°F | 6 | 6.7 in |
| February | 34°F | 11°F | 7 | 8.6 in |
| March | 45°F | 21°F | 8 | 8.6 in |
| April | 56°F | 31°F | 10 | 8.0 in |
| May | 67°F | 42°F | 12 | 1.7 in |
| June | 77°F | 53°F | 12 | 0.08 in |
| July | 84°F | 58°F | 10 | 0.0 in |
| August | 82°F | 56°F | 9 | 0.0 in |
| September | 74°F | 46°F | 7 | 0.2 in |
| October | 59°F | 34°F | 8 | 3.1 in |
| November | 45°F | 22°F | 6 | 6.4 in |
| December | 34°F | 12°F | 6 | 7.2 in |
Regional differences
- Warmest winterRapid City: January high 36°F
- Coolest summerKeystone: July high 79°F
- Most wet daysSioux Falls: 104 a year
- Fewest wet daysRapid City: 96 a year
- Most snowKeystone: 60.9 in a year
Warmest and coolest South Dakota city each month
| Month | Warmest | Coolest | Best month for |
|---|---|---|---|
| January | Rapid City 36°F | Aberdeen 24°F | – |
| February | Rapid City 38°F | Aberdeen 29°F | – |
| March | Rapid City 48°F | Aberdeen 42°F | – |
| April | Sioux Falls 59°F | Keystone 51°F | – |
| May | Sioux Falls 71°F | Keystone 60°F | 3 cities |
| June | Sioux Falls 81°F | Keystone 71°F | 2 cities |
| July | Rapid City 86°F | Keystone 79°F | – |
| August | Rapid City 85°F | Keystone 78°F | – |
| September | Rapid City 76°F | Keystone 69°F | – |
| October | Sioux Falls 61°F | Keystone 55°F | – |
| November | Rapid City 47°F | Aberdeen 43°F | – |
| December | Rapid City 37°F | Aberdeen 29°F | – |
By normal daily high. "Best month for": how many of the 4 cities have it among their best months by our comfort score.
Frost and humidity across South Dakota
- Earliest typical last frostSioux Falls: May 1
- Latest typical last frostKeystone: May 28
- Most muggy daysSioux Falls: 29 a year
- Fewest muggy daysRapid City: 1 a year
All South Dakota cities
| City | Jan high | Jul high | Wet days/yr | Snow/yr | Best months |
|---|---|---|---|---|---|
| Aberdeen | 24°F | 85°F | 98 | 42.7 in | May |
| Keystone | 36°F | 79°F | 103 | 60.9 in | Jun |
| Rapid City | 36°F | 86°F | 96 | 53.7 in | May, Jun |
| Sioux Falls | 27°F | 85°F | 104 | 45.3 in | May |