I don’t think they are ever hot in the OT. Plus wouldn’t the hilt get too much to handle after a while, if they were?

Of course in the Phantom Menace we see lightsabers melt through a set of strong looking metal doors in the first five minutes of the movie. Compare to Luke cutting the hatch on an AT-AT, which should theoretically be sealed better than “a space door.” *

The heat has also been used to explain why lightsaber wounds aren’t horribly bloody… (Someone please tell Ponda Baba)

Remarkably, in Return of the Jedi, we see Luke’s saber acting like a baseball bat against Jabba’s thugs. Not sure if it’s hot or not.

This is not a paid ad for hotornot.com which I remember used to be a fun site around the same time Phantom Menace was released.

*Ok I guess it’s not just a space door; the room must be sealed if the Jedi are to be poisoned, but who has poison cannisters in their AC system? A system that services only one room and not the whole ship?? Do Nemoidians have a special room to murder all their guests this way? Maybe it IS just a space door. Ok ok in real life it would be a bulkhead that could seal a hull breach. Still doesn’t explain ventilation. I think it’s a space door.