Honey bees are not cold-weather flyers. Their muscles seize up if they get too cool. When this happens, the result is the stuff of nightmares--a bee may be alive and otherwise healthy while she lays on the cold ground unable to move herself to warmer climes. (Gen X'ers may recall Metallica's horrifying video for the song "One.") She'll ultimately succumb to the cold unless the weather quickly changes in her favor.
Beekeepers usually espouse 50° as the minimum temperature a bee will venture outside the hive, and that's not entirely untrue because 50° is the lowest temp in which a bee can fly for prolonged periods. But we've all seen bees flying on days when it wasn't 50° and wondered why they weren't following the rules we gave them.
Enter an article in the January 2018 American Bee Journal titled "Cold Flying Foragers: Honey Bees in Scotland Seek Water in Winter." It's the most interesting bee-related article I've read for months, and it explains how bees thermoregulate their thorax temperatures to make flight under 50° possible (but only for short distances). I've spent so much time thinking about this new information that I decided to make it part of a beekeeping display at an upcoming festival. The picture above is the visual aid I made to spawn discussion with festival attendees. I hope you find as insightful and fascinating as I do.