According to the NOAA, Montana was -15.6F below the 1901-2000 mean

Norht Dakota was -14.8 below. South Dakota was -13.5F below.

Coldest February ever in Montana , South Dakota and North Dakota and 5 other states was 1936.

Feb 1936 looks very much like Feb 2019. I hope the summer of 2019 is not the same as the summer of 1936. That would be bad!!!!