I’m used to seasons that start on June, September, December and March on the 21st, at least officially. But here in New Zealand, we like to simplify things (I hope my only New Zealand follower will agree) and we decree the beginning of each season at the beginning of the month. It suits me perfectly for spring (first September), summer (first December), fall (first of March), I would only like winter to start on June 21 and end on August 31, which seems pretty reasonable to me.