Rates were so much higher for my dates a year ago! (12/12-12/17)
The sweet spot was actually early November. Alas I booked mid.
El convento didn't even have any bookings a year out. They started maybe around march and it was in the 400s, and bottomed in the high 100s (just under 200) in early Nov. embassy was as low as 134 at one point. Sheraton OSJ had a suite solidaky under 200. Was pretty cool.
I'd lock something down but make sure it can be changed, then keep checking back.
Not sure how dates in the runup to Xmas compare to January, but maybe my experience isn't unique.