Thanks for the replies. I made a bit of a mistake in not explaining in more
detail - I was only referring to the outside of the hive. I know this is
widely practised elsewhere (painting the outside), but in the UK, the use
of cedar means hives are not normally painted. Following on, the text books
in the UK never recommend painting the outside?

Now I can understand this, if a particular peculiarity of English weather
meant more moisture ended up inside the hive (than other countries), and
not painting the outside may well have developed as a result of
experimentation based on local climate. There is no economic reason I can
see why people avoid painting the hive.

With the switch to open mesh floors - for Varroa control, we have
effectively opened 1 "surface" of the hive. I was interested in the
comments about it being like a hot air balloon, but still am not convinced -
 a balloon has a very narrow neck at the bottom and a very high temperature
going in. A hive would have much less surface area relative to opening - so
would moisture and wind regularly replace this "dead" air inside?

Thanks (again)

A.

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