Hive Heating in the Winter

By Gary S. Reuter, Department of Entomology, University of Minnesota

In this article I would like to discuss the factors in a honey bee colony that pertain to winter and early spring. How does a colony make it through the cold winter? What are some of the hazards? What can we do to help?

I am not going to go into step by step how to prepare a colony for winter. For this you can go to and find Beekeeping Information under the Bee Squad heading. Under our Free-bee Information section, you can download information on the steps for commercial winter cover or tar paper.

There are some similarities between the way the bees heat their hive and we heat our homes. There are also a lot of differences.

First we need fuel (gas, oil, electricity, solar, etc.) and so do the bees. The bees use honey for their fuel. Imagine what would happen in the middle of the winter if you ran out of fuel with no way to get more! This can happen to the bees if you do not leave them with enough honey in the fall to get through winter. One big difference is that the fuel is also their food so they don’t usually freeze to death but rather starve to death. Not that that is much of a distinction if you are the bee because you are dead either way.

A major difference between bees and us is that we heat our entire house; the bees only heat the area they are in at the time. It would be like gathering your family together under a bunch of blankets on the bed to stay warm with no other heat source. You really would not care how cold the room is as long as you have enough blankets and can stay under there bundled together. I hope you brought enough food under the blankets with you!

The bees do not have blankets so they cluster together in a ball to stay warm. Some of the bees are on the outside of the cluster with the hairs of their bodies touching providing the “blanket” or insulation. The bees on the inside of the cluster are around the food and will eat it and flex their flight muscles (shiver) without moving their wings to create heat. So the bees create heat just like you would under the blanket. The colder it is the tighter they cluster together. The bees take turns and rotate jobs on a periodic basis. One day a bee is a blanket the next she may be a heater.

What happens when you run out of food under the blanket? Someone will have to go get more food or you will starve. How can you do that without freezing to death? It may depend on how cold it is outside. Can everyone go and bring the blankets to keep warm or should just one person run and bring back a load of food?

This happens to the bees when they run out of food under the cluster. If all goes well with the weather there will be days when it is “warmer” and the cluster can expand. During this expansion they can move the cluster to access more honey. If it stays very cold for an extended period of time the bees cannot loosen the cluster to move to more food.

Most of us heat with some kind of combustible fuel (oil, gas). This causes a large amount of air to be passed into the house to provide for burning of the fuel and exhausting of fumes. Bringing outside cold air into the warm house causes the humidity in the house to be low. If you have electric or solar heat you would actually have high humidity in the house. Bees use internally produced heat and moisture is produced from metabolizing honey; therefore, without ventilation, their hive will have high humidity. High humidity is not good for insects in the winter. Therefore, you must be sure to leave openings for ventilation to bring in some drier air.

Speaking of entrances, now you know why you must leave an entrance. You should provide an upper and a lower entrance. You should be careful not to leave a large entrance on the bottom that would allow mice to enter the hive. Mice are a problem because they build a nest in an unprotected (by the bees) area and destroy comb and stink up the hive. So how small of a hole can a mouse fit into? I have used 3/8” entrance reducers for years and have not had a mouse go in. EXCEPT when they chewed out the reducer to make the hole bigger. They did not have to make it much bigger; in fact I think they just needed to round if off. I have now stapled a piece of 8×8 hardware cloth on the opening so they can’t chew it. You can use any metal you have around.

What you need to have to get a colony through winter is (in no particular order):

  • Sufficient population of healthy bees
  • Enough honey
  • Healthy young queen
  • Adequate moisture control
  • Pollen stores available in late winter

For more from Gary:

Entomology website:

Gary’s website:

Lab website:

5 thoughts on “Hive Heating in the Winter

  1. Phillip

    The second to last sentence recommends #8 mesh over the entrance. Isn’t this too small for bees to pass through?

  2. Jim Hayes

    I have 5 acres next to the Bay it is surrounded by a golf course and 5 acre lots is this a suitable place to raise bees

    1. Kelley Beekeeping

      Hello Jim, it sounds like a suitable place, We would recommend to place the hives as far away from the golf course as possible to prevent accidental stinging. Also, watch putting the hive to close to the bay as water and moisture attract small hive beetles.

  3. Sue Lang

    To alleviate winter starvation I have always been told to put solid food (Fondant) on top of the brood box frames within an eke for easy access for the bees Your article suggests that the bees head down the hive (under the cluster) for more food stores. Therefore should I put solid food under the brood box – on the floor?

  4. Carol Sharp

    My bees are all dead. I was planning on putting the blanket on today, and found they froze to death? I live in Chicago, and it was cold just a couple days, maybe 26 degrees, but mostly 40’s and 50’s on and off. I also gave them super sugar water with special spiralina. And I made pollen patties, and put them on one super and one honey box with straw for the moisture. I was advised to put the blanket on this week???
    What happened?

    Thanks, I am soooooooo sad.