I would not count on that. The evidence seems to suggest that climate change will increase the extremeness at both ends, rather than trending warmer in winter. Global warming is a mean, across both miles and months. One other thing to consider is the collapse of the AMOC, which transports tropical warmth to more northerly climes. When it stalls out, the north sea will probably ice over in winter (which it has not done in a very long time), which will mitigate warming just a tad but probably cause other problems.