I dont know what is going on but our balcony cabin on the Horizon last year in January was about 77 degrees early on during the cruuse. Called maintenance, they tried to fix it. It cooled down to the mid 70s. Not ideal for sleeping that's for sure. I noticed our cabin on Mardi Grad was slightly warmer than normal this past January. Prior to this I always thought we had cool cabins.
Generally, I am always cold and never hot.
Maybe they are adjusting the temps!