Winter Cluster

Collective Thermoregulation

Honey bees do not hibernate. They remain active throughout winter, maintaining a warm cluster inside the hive by burning honey as fuel and generating heat through muscle vibration. Individual bees would freeze within minutes at near-freezing temperatures, but thousands of bees working together create a living thermostat that keeps the colony alive through even harsh winters.

The cluster forms when outside temperatures drop below about 57 degrees Fahrenheit. Bees on the outer shell pack tightly together, forming an insulating layer. Bees deeper in the cluster vibrate their flight muscles (without actually moving their wings) to generate heat. The core temperature is maintained around 93 degrees Fahrenheit when brood is present, dropping to about 70 degrees in broodless periods. Bees rotate between the warm interior and cold exterior positions to prevent those on the outside from freezing.

Moving Through Stores

The cluster is not stationary. Over the course of winter, it slowly migrates upward through the honey stores as it consumes its food supply. This is why experienced beekeepers ensure that honey frames are positioned above the brood nest going into winter: the cluster naturally moves up, and if it encounters empty frames with no honey before spring arrives, the colony starves, often with full frames of honey inches away in a direction the cluster did not travel.

Florida Winters

In Bradenton, our winters are mild compared to northern states. Our bees rarely form tight clusters, and brood rearing often continues year-round. However, we still manage for winter by ensuring adequate food stores, reducing entrances to promote heat retention and discourage robbing, and monitoring for the varroa mite spikes that typically occur when brood production slows.