[GregB]

People keep asking all kinds of winter related questions.
Like - can I open a hive to give them dry sugar in 40-50F?
(Of course you can; in fact, you must if they have no food).

But here is the deal - you can do pretty much anything you want in sub-freezing temperatures IF there is a pressing need for it. Of course, this takes some preparation and planning before hand AND you must be quick.
Just do what needs to be done and don't worry too much (especially if the alternative is dead bees anyway).

Few videos (temps in the videos are about 20-25F - about perfect for these kinds of projects):
Inspect if must -

Combine if must -

Split apart if must -

Another winter combine:

All kinds of examples on Youtube - just search for "объединение пчел зимой"

 

[LAlldredge]

You recommended one last year that had plastic clear inserts on top of the bars. They used the condensation for water. Couldn’t understand a thing but the guy knew what he was doing. I open the top part of my stacks all winter long to pour sugar through a screen and spritz water. Today at 30 degrees. Takes less then 1 minute. No big deal if you are prepared.

Winter is one of my favorite seasons to beekeep as odd as that sounds. What you do has a major impact. I also think we can shave off another 10-20% off losses if done well.

 

[AR1]

I had a hive I opened occasionally all winter long, even in below zero temps. They survived. But I stopped doing it when they got mad and a bunch flew out and attacked me. I was surprised, since when it is cold they usually don't fly out. These were a pretty grumpy hive anyway, and seeing these bees zooming around in the zero temps...few of them made it back inside.