Used to be pretty consistent that Typhoon Lagoon would close in the Nov / Dec timeframe, and Blizzard Beach in Jan / Feb. However, last year they switched the schedule. TL had some physical construction work planned as well, and by schedule its rehab second, they wouldn't run into additional conflicts with BB if the TL rehab ran longer than expected.
Additionally, there is a long-standing rumor that Typhoon Lagoon may ADD a couple of new attractions this winter. If so, one can theorize that its rehab may again be scheduled after BB.
In the end, I think the only way to really know for sure is to wait for the schedule. Rest assured that one of the two will be open when you visit, and they both have their charms.