An upper level trough remained over the Northern Plains from December 1 through December 6, bringing colder than normal temperatures and some light snow to the northern Black Hills and Bear Lodge Mountains. On the plains of western South Dakota and northeastern Wyoming only a few snow flurries fell. On December 8 above normal temperatures returned to the region and continue through December 27. Temperatures were well above normal on December 8 and 9 when many locations pushed into the 60s. Through this period the weather was mainly dry except for a powerful snowstorm that moved through the southern plains on December 19 and 20. This storm brought 6 to 12 inches of snow to Todd, Tripp, Mellette and Bennett counties in south central South Dakota, with little or no snow falling across the rest of western South Dakota and northeastern Wyoming. On December 28 a powerful snowstorm moved through the southern plains and brought colder temperatures to the region the last three days of the month. This storm also brought mainly light snow, two inches or less, to northeastern Wyoming and western South Dakota, with heavier snows falling in south central South Dakota where 3 to 6 inches of snow fell.
Temperatures averaged 3 to 6 degrees above normal in December, with every location reporting above normal temperatures. Averages ranged from 1.6 degrees above normal at Pactola Dam to 7.4 degrees above normal at Lemmon.
December was a dry month, with only south central South Dakota and portions of southwestern South Dakota receiving above normal precipitation. Rainfall deficits for the month averaged 0.30 inches.
Snowfall across southwestern and south central South Dakota was above normal with 7 to 14 inches of snow. Elsewhere in western South Dakota and northeastern Wyoming little or no snow was reported.
| Temperature Data | Rapid City | Lead | Gillette | |||
| Temperature | Date | Temperature | Date | Temperature | Date | |
| Maximum Temperature | 62 degrees | 9th | 59 degrees | 8th | 59 degrees | 8th |
| Minimum Temperature | -7 degrees | 7th | 3 degrees | 3rd | 1 degree | 3rd |
| Precipitation Data | Rapid City | Lead | Gillette | |||
| Monthly Data | Amount | Data | Amount | Date | Amount | Date |
| Precipitation | 0.04 inches | 0.24 inches | 0.02 inches | |||
| Snowfall | 2.4 inches | 2.5 inches | 0.4 inches | |||
| Daily Data | ||||||
| Maximum Precipitation | 0.02 inches | 6th | .07 inches | 29th | 0.02 inches | 28th |
| Maximum Snowfall | 1.4 inches | 6th | 0.7 inches | 1st | 0.4 inches | 28th |
| Temperature Data | Western South Dakota | Northeastern Wyoming | ||||
| Temperature | Site | Date | Temperature | Site | Date | |
| Maximum Temperature | 69 degrees |
Winner |
10th | 65 degrees | Colony | 8th |
| Minimum Temperature | -21 degees | Cottonwood | 7th | -8 degrees | Upton 14ENE | 3rd |
| Precipitation Data | Western South Dakota | Northeastern Wyoming | ||||
| Monthly Data | Amount | Site | Date | Amount | Site | Date |
| Maximum Precipitation | 1.55 inches | Winner | 0.26 inches | Wright 12W | ||
| Minimum Precipitation | 0.00 inhces | Usta 8WNW | 0.02 inches | Gillette 4Se Upton | ||
| Maximum Snowfall | 14.0 inches | Mission 14S | 4.1 inches | Wright 12W | ||
| Minimum Snowfall | 0.0 | Usta 8WNW | Trace | Rockypoint 1N | ||
| Daily Data | ||||||
| Maximum Precipitation | 0.90 inches | Mission 14S | 21st | 0.15 inches | Wright 12W | 29th |
| Maximum Snowfall | 10.0 inches | Mission 14S | 21st | 2.3 inches | Wright 12W | 29th |
| LOCATION | DATE | NEW RECORD | OLD RECORD | DATE |
| Redig | December | Trace Precipitation | Trace Precipitation | Last Year 2001 |
| Redig | December | Trace Snowfall | Trace Snowfall | Last Year 2001 |
| Deviles Tower, WY | December | 0.06 inches Precipitation | 0.07 inches | 1991 |