1941
So the -37F was at the airport as well as the -33F in 1984.
We just haven't had that perfect arctic high in place where we pull off a sunny high of 5F with light winds and deep snowcover where CON can just drop off from 4pm onward. The city has built up a bit too, but if they could pull -33F in 1984 I'm sure they could still do it now.