Yeah late winter/early spring will be some of the worst flying conditions there will be in that area. When its -20F, its often just too cold for clouds, icing, precip, etc.
But when its 20-35F, there is enough moisture for low ceilings, fog, lots of icing, etc. I flew into there in 2000-march 2001 every morning for freight. Sometimes I got really iced up, and ILS approaches were almost an everyday occurance, and always right in the middle of the early morning rush. Heck everything else i have done since has been a cakewalk