I never really understood what "winter is over" really means.
We've had snow in a sea of warmth like March 2016, Feb 2018, January 2012. Heck the book about the 1888 blizzard talked about an early spring and early flower growth before the storm (probably late season severe blocking occured).
Even if we go ++++AO NAO EPO mega RNA it doesn't mean there is NO SHOT of winter weather or a late return.