Bees are picky about their hive temperature -- 94º. (If you're a Star Trek fan, you can see that the writers for that show did their research when they made up the borg hive cubes.) Anyway, when the hives get hot, the bees get busy cooling it down. When the sun hit our hives this morning, Adam said the bees went crazy -- clouding outside the hive and buzzing so loudly he could hear them over on the patio.
They did it again later. I took a picture of this hive. The bees exit the hive, sometimes fanning the opening with their wings. They stay out until the hive cools down.