When it is cold the bees cluster up and keep the interior of the cluster at around 90 degrees. They do this by shivering their wing muscles. The 40s are a good temperature. The bees use the least amount of energy. The colder it gets the harder they have to work at keeping warm. If it gets warmer outside they start flying. Of course this is an exercise in futility since there's nothing to forage. Energy is wasted. Note they are keeping the cluster warm not the whole interior of the hive.

Are they alive? If you put your ear to the side of the hive, give a good sharp rap, you should hear a hum in response. Or if it is in the 40s or warmer, the sun is out, and there's little wind you will probably see them flying. Bees keep their hive relatively clean. They'll go out for a cleansing flight (aka take a poop). In the snow you'll see lots of small yellowish-organge dots.

Sometimes the lower entrance gets clogged with dead bees. If it is and it is in the 40s+, sunny, no wind, use a long stick or dowel rod and open the entrance as best you can. You'll clean the bottom board off in the spring.

If you bought your equipment from us the inner cover has a slot. This is designed for ventilation and an upper entrance. Make sure the top cover is slid forward so it is open.

Are they dead? No hum? No observation of flight? You can wait until spring. That's hard, isn't it? Or wait until that warm day to pop the inner cover and see if they are actually alive. If you do this be very brief in case they are still alive. They'll fly. Then they stick to you and won't fly off like in the summer. It's too cold and you are (relatively) warm. You'll need to brush them off with a bee brush.

More in part 2: Dead or Alive.