These two pictures of the same hive may be the opposite of what you’d expect.
This first picture was taken at 8AM, temp about 75 deg F
This second picture was taken at 2PM, AIR temp around 100 deg F..
In full sun!
While bees ‘hangin’ outside the hive are a product of high temperatures it
is also a product of the population at the hive at any given time. The number of
bees on the outside does not necessarily reflect the amount of difficulty in
maintaining the internal temperature. My opinion is that in late afternoon
or early morning many foragers collect on the outside so that they don't
add their biological heat to the inside. During the day those same foragers are out...probably