On the surface, the question “why is there winter?” Seems pretty naive, juvenile, sophomoric. At its most basic level, the answer is simple, there is winter because we have defined a season of the year that we call “winter.” And this winter, has certain characteristics regarding temperature, humidity, precipitation and or climate in general that collectively form a pattern of about three months each year that often offer the least comfort level tolerable for human beings who can read, and or speak the language that this winter is defined in.
Put more simply, if winter were bad enough to kill us all, there would be no more winter, because there would be no more people to bitch about it. Just a bunch of heartier, lesser evolved animals. The jury is out as to whether or not they would stand around wondering where all the people bitching about how cold it is went.
So, winter is because it is, because the Earth revolves around the sun and it tilts now and then in a different direction as it makes its annual Journey.
And if you don’t like that answer, move the fuck to Florida why don’t you?