Unseasonably warm days will have your bees out and about, flying and foraging when little is blooming. They're burning lots of calories but bringing nothing home. They have no thoughts of clustering and chances are they've eaten quite a bit of honey that would normally be close to the brood nest. Without honey stores in contact with the cluster, this first Wintery cold snap may be a colony killer. It only takes 3 days for a colony to die from isolation starvation, and we've got 6+ days to worry about.
Insulation can give your bees the extra time they need to move and form a proper cluster. Don't wrap the hive tight, just make sure their heads are warm. The other thing you can do — TOMORROW the last of the warm days — is make sure the honey combs are butt up against the brood nest. Remove all empty combs between the nest and stores. Believe me… I learned the hard way… the bees will not leave brood to cross a single empty comb to get food. Don't worry about breaking the propolis seal and disturbing them. They need the food more than the draft-protection.