will the pool be open over christmas thru new year? is it heated

Yes

Don't know and don't want to know

At least one pool stays open through the winter at both MGM Grand & Signature, heated, with limited hours from 8 to 5. Hot tubs are open also.

At least one should be heated at all times. I would call their desk just to make sure, though (:

Heated to around 80 degrees

One pool is opened year round