Actually, if it's loose, color doesn't matter.  The air will circulate &
insulate.

But if it's tight fitting, be prepared to sweat - a lot!

I just attended the re-dedication of our county courthouse - it's 100 years
old!  There was a lot of pomp and circumstance, and it was officiated by the
Free Masons of Indiana  (http://www.indianafreemasons.com/index.html)- most
were older gentlemen and they were all wearing their ceremonial garb - which
are black suits! and their funny hats LOL  Most of them were able to be in
the shade (of a tree almost as old as the courthouse), but some got stuck in
the hot sun!  The Free Masons were there because they were the ones that
originally laid the cornerstone in 1907 - and the time capsule that was with
it.  Since the building is still standing (and they recently cleaned the
copper dome), they could NOT get to this time capsule - they did, however,
find where it is with ground penetrating radar (not at taxpayer expense,
this was paid for by the Monroe County Historical Society - and they
collected donations), and in the printout was another blob, that they didn't
know what it was.  A great-grand-daughter of one of the original workers
said that it was a whiskey bottle (stolen from her great-grandfather by his
co-workers and hidden in the cornerstone - no one's sure if this is true or
not, but it's an interesting story).  They do have a listing of what is IN
the time capsule.  And they have assembled a new time capsule to be opened
in 2107 (not sure where they're going to place it)!  Included in it is an
iPod (and I'm assuming instructions on how to use it - lest future
generations forget), with music from local musicians and a broadcast from a
local radio talk program that discusses local issues and hot-topics (sorry,
no Rush Limbaugh), among the usual newspapers and other items of this era.