Not sure about that. It seems a struggle to get winter means above freezing above around 63N, even on the coast. Trondheim, at 63N, averages slightly under 0C Dec-Feb. Further up north Narvik averages a few degrees below freezing and further north still Tromso and Hammerfest average 4/5C below zero. Rainy Bergen, at 60N, is surprisingly cool (1/2C) considering it's coastal position and relatively low latitude.I'd say the UK is possibly the most northerly country in the world that can go an entire winter without much/any wintry precipitation/temperatures, at least at low altitudes. Other relatively mild locations further north I.e coastal Iceland and Norway, Faroe Islands etc routinely see sleet/snow in the winter months, even if many places there average above 0C in the winter.
On the flip side trees don't grow above 53N in parts of Labrador, Canada. The same latitude as Manchester. Shows the influence of a cold current vs a warm one.