When temperatures are cold, can be a bad idea to open the beehive. Opening the hive can break up the cluster. And possibly freeze the colony to death. However, there are several ways to see how your hive is doing without opening the lid.
First, you can place your ear next to the wall of the beehive and knock on the hive. You will hear live bees buzzing inside.
Another way is to look for a spot of melted snow on the outside of the lid, usually in the center. A healthy colony will form a cluster inside the hive around the honey stores. The heat from the cluster will melt the snow on the outside of the lid. Or if the snow is melted, it will cause the spot in the center to be drier than the rest. Don’t worry if this spot is off-center. It means bees are clustering on one side.
A third way is to lift the hive and guess its weight. A hive full of honey stores will be heavy. We like a two-story hive to weigh about 100 pounds going into winter.
Remember that the critical time to feed bees is in early spring (February-April) when the bees are brooding up and stores are running low. In December and January, they should have plenty, assuming hives were heavy enough going into winter.