you can do it when you want to really,some people have theirs already hibernating,i am winding mine down now and should be ready to go down around the 15th.I was going to hold out until december but one of mine started to wind herself down so they are going a little earlier.
yeah as already stated tbh, i put my hermans into hibernation today, for the 2nd time, he refused to go down the first time 2 weeks ago, but fingers crossed he'll take to it this time and go to sleep.