Hive ventilation is critical to timely ripening of nectar into honey and for wintering of colonies. Bees control ventilation to maintain proper humidity for nectar ripening. Bees can cool their hive on the hottest summer days by fanning air over droplets of water (called "air conditioning"). They arrange an incoming stream of air into and out of the colony. Carbon dioxide levels can be similarly controlled.
Bees may exit their hive in the hottest part of the day to beard on the outside of the colony or beneath the bottom board.
During colder temperatures, bees form into a cluster on several combs or frames. Clusters have an outer shell of bees to maintain a proper internal temperature. As outside temperatures get cooler, the outer bees that form a shell move inward. As temperatures drop, the cluster becomes more compact.
See also cooling hive, clustering.
PerfectBee Blog. n.d. Fat Bees and the Winter Cluster. Perfect Bee. Accessed 2023. https://www.perfectbee.com/learn-about-bees/the-life-of-bees/fat-bees-and-the-winter-cluster
“What a Healthy Winter Cluster looks like!”. YouTube, uploaded by Kamon Reynolds – Tennessee’s Bees, 13 December 2020. https://www.youtube.com/watch?v=ihLM2H2EgnY
Ellis J. 2016. Colony Level Thermoregulation and the Honey Bee Dance Language. American Bee Journal 156(2): 147-154. https://bluetoad.com/publication/?i=286589&p=31&view=issueViewer and https://bluetoad.com/publication/?m=5417&i=286589&view=articleBrowser&article_id=2363043&ver=html5