Snake go by temp, light cycle and MAINLY pressure changes in the atmosphere. If you can simulate barometric pressure changes in the environment of the snakes then power to you. I have heard of people pairing as early as starting to pair in August.
Breeders who breed year round are only in it to make the most amount of babies the quickest. Any big breeder or breeder who know what they are going with success and numerous babies under their belt have a "season" for breeding.