Honey bees mostly stop flying when the air drops below about 50 to 55 degrees Fahrenheit. The University of Maine Cooperative Extension puts the minimum temperature for honey bee flight at 54°F and says activity peaks between 72 and 77°F. That is why our six hives in Libertyville go quiet on gray October mornings and come back to life when the afternoon sun breaks through.
The limit is not the wings. It is the flight muscles. A worker honey bee (Apis mellifera) has to warm her thorax before she can beat her wings fast enough to lift off, and entomologist Bernd Heinrich found that takes a thorax temperature of at least 77°F. She gets there by shivering those muscles in place, a little like stamping your feet at a cold bus stop.
Once she is airborne, a forager runs hot. A 2021 study in the Journal of Experimental Biology notes that a flying honey bee often keeps her thorax about 18°F warmer than the air around her, and that foragers leave the hive with a thorax near 97°F. Cold air pulls that heat out of a small body fast, so on a chilly day a long trip to a distant flower is a gamble.
Bees never leave the hive cold. They warm up first, then go to work.
Temperature is not the only thing that keeps a hive home. The same Maine extension guide says rain, wind above 15 mph, and heavy cloud can stop foraging even on a mild day, and that bees will not fly in the dark at any temperature. The rule of thumb also bends. In the American Bee Journal, Ann Chilcott and Cornell biologist Thomas Seeley reported bees in Scotland collecting water from a dish on winter days as cold as 39°F, on 22 of the 27 days they watched in early 2017.
So if you visit our campus this month and see bees drifting around the hives on a sunny 60-degree afternoon, they are making the most of the warm hours before winter. On the cold days they stay in and keep each other warm, which our family understands. We would rather give you the straight answer than the tidy one, and for a honey bee the straight answer is about 54 degrees, give or take the sun.
