Well, I'd put WI/MN as harshest anywhere. You get that dry super cold air with no snow. The first sign of winter used to be when your nose froze shut when you breatheAs a native of St. Paul, MN, and an 18 year resident of Denver, I can guaranfuckingtee you that WI/MN winters are far more harsh the Denver's.
Denver is not in the mountains, so the snow they get isn't as often, and it never sticks. 1-2 feet of snow one day can be melted away less than a week later.
When I lived in MN it was International Falls and Duluth though so I always think of it as really cold.
But yeah, it actually looks like cleaveland and denver are pretty much on par.