I don't know. It hasn't struck me as unusual yet. As a child, I always noticed it as working something like this:
It would stay unpleasantly hot through Halloween so as to cause any good costume to be untenable due to the need to wear shorts and shortsleeves.
Then it would cool down.
Then it would get unpleasantly hot again in late February/early March just in time for the Rennaissance Festival, leaving you wandering the fair panting for water and shade.
I believed the weather was out to get me.
I guess I was paranoid as a kid.