We were just on the Holiday 2 weeks ago. It was cool the first evening (still close to Mobile). But the next day at sea it was probably around 87. Cozumel and Playa Del Carmen were about 90, and the last day at sea was also around 87. It was very cold inside the Americana lounge both during the day and at night during the shows. We wore pants and long sleeve shirts. I even saw one guy leave and come back with the bath robes from their cabin to cover up with.
At night when the ship is sailing through the ocean, and you go out on the balconies to look, we didn't get cold but is was very windy.
There were not thermostats in our room but you can change the amount of air that blows in your room by screwing in or out the vents. We were comfortable in our cabins.
Hope this helps - Hope you have a great time.