For the last five years that I've been keeping bees I've always had to deal with bees that were in the extremely defensive to down right HOT! category. This year I don't know what changed. All five hives are as calm as butterflies. I didn't know working bees could be so much fun. This time last year I was contemplating having to requeen them all. I couldn't work them without being literally covered in defensive bees and being headbutted constantly. Same bees, longer winter, still no chemical treatments. They are busting at the seams and I'm going to split them all in a week when it warms up. Hope this behavior continues. Since this winter has been what it has, could/does weather patterns affect agressiveness? I've done splits in Feburary, but not this year.