Now I am not exaggerating about the past where Rapid City had temp . way above Eastern Dakota, and tens of degrees from the part of Minn. I am in BUT i checked recent lows for Rapid City and it seems in very recent years -30 has been common there, with -20 in five or six years earlier more normal.
Hot Springs, South Dakota though is recorded as being the warmest city in South Dakota with an average of 25 daytime highs at 50 degrees being the norm from Dec.- Feb.
I do not like above freezing temp. once snow is on the ground in Dec., period, so I do not think I would enjoy living their myself.