It's HOT in here!
Even in Highland the weather can get warm. Here, the bees moved outside just prior to some stormy weather so they could keep cool. The brood inside is still being kept at 94 degrees F by their sister workers. By evening they had all gone back indoors.
These small colonies, three boxes with 5 frames each are referred to as a "nuc" - as in nucleus. It has all the component parts to grow into a big colony: queen, several thousand workers, a handful of drones and drawn comb.