If the winter solstice is the longest night of the year, why does it mark the beginning of winter, rather than the very middle of it?

Question

If the winter solstice is the longest night of the year, why does it mark the beginning of winter, rather than the very middle of it?

In: Earth Science

Answer 1

It doesn’t mark the beginning of winter, but it isn’t the coldest day due to something called seasonal lag, basically it takes a long time for the oceans around the continents to cool down keeping the land next to it warmer for longer. https://youtu.be/2i8MX73Uhyo