There are three different definitions of winter.
Solar winter is the quarter of the year with the lowest sun angle and shortest days.
Meteorological winter is the coolest quarter of the year with the lowest average temperatures and the most snow and ice.
Astronomical winter is the most familiar to you! Astronomical winter has to do with the earth position in relation to the sun. It begins durin the winter solstice (when the sun is lowest in the sky) to the spring equinox (when the sun is directly over the equator).
So meteorological winter and solar winter are already over, that's 2/3. Not bad. 19 days to go and it will be spring on every calendar!