Ahh...brumation....
It changes every year for me depending on my schedule. One year I went to Europe from January to May so I brumated them almost the entire time. (I had a friend check on water and start warming them up in mid-late April.
Usually, however, I do it sometime in November or December and take them out about sometime in February or March. Last year it was the weekend after Thanksgiving to Valentines Day. This year it is going to be right after the SC show (Nov 4-5) to Valentines Day. Valentines Day is a good calender mark for me as it gets them hatched in plenty of time for the Daytona Show and the other fall shows...yet, not out too early to have to mess with babies forever! (Plus, the longer they are up, the more they eat and now that my adult colubrid collection is up to about 500 mice a week...it gets pricey!) Also, if up by Valentines Day, then shedding starts around St. Pats day or later and breeding commences right around my April Fools birthday. Sort of a little present for me and everything hits the holidays so I don't have to look at a calendar. Eggs then come mid-late May with babies hatching end of July early August, feeding in a week or two and ready for Daytona and the Fall shows.
More than you probably care to know...but I'm in a mood to type it all in.
Cheers.