In reply to Emilysaladfingers:
Rainfall amounts average the same as November,and this month has been mostly dry and sunny (sometimes hot too) apart from one wet week, when apparently it was still dry enough in the caves.
The difference appears to be that it'll be 5 degrees colder. On the first day of our trip at the beginning of this month we were wearing 3 shirts and a waterproof to stay warm, though it did warm up after that.