when do you stop wrapping up your outdoor buns?

In my first winter as a returner to buns, I'm wondering when people stop covering them over with extra fleeces, blankets, duvets, tarps etc? Do you wait until its consistently warmer, or do you chop and change each night depending on the temperature?
My 2 have tons of hay and each other, plus a hutch cover, plus fleecy blankets plus a waterproof tarp but this morning their hutch cover had condensation on the inside as obviously it was much warmer last night than it has been. Inside the hutch was fine, just warmer than of late. I don't know whether to take the blankets off while its a bit warmer and then put them on again when the temp drops to minus or just to leave them as they are. I don't want them sitting in a damp atmosphere as a result of it being warmer.

Mine are shed buns so its hard for me to say but I would judge it by how many layers you feel you need on to go out and see them. A week ago I had on a jumper a fleece down jacket hat and gloves now I am happy with just the fleece. Could you reduce the amount you put on?