September isn't a bad time to start in my opinion. As the majority of the flying will be with your instructor anyway, therefore reduced visibility and higher winds (than the student < 10kt rule) would not mean the flight would be cancelled, however if you were trying to go solo in the same weather conditions then maybe it would.
By the summer you would hopefully be onto wanting to get solo, which is the best time to go solo as far as weather is concerned. Traffic is another matter
I have spent the winter trying to go solo, and it has happened, however it's been hard (if you read my blog you will see the lessons in between going solo when the weather isn't good enough etc).
Good luck and get at least half of those exams nailed before you start flying!