We live in NW Florida and we do not have A/C or Central heat.  It gets
into the high 90's during the summer with occasional forays into the
100's and in the winter we get below freezing for several weeks a year.
Our fuzzies are fine with this.  During the summer, I make sure there
is plenty of cool water to drink.  If somefuzzy seems too warm, we go
swimming to cool off.  In the winter I wrap the cage on three sides with
a heavy blanket and provide lots and lots of blankets.  During the summer
I use old sheets and pillowcases for bedding.
 
Ferrets seem to be very adaptable, just like humans, if they are allowed
to acclimate to the environment they live in.  (I know if I'm in A/C
during the summer, my house seems alot hotter than if I'm not in the
A/C.)
 
Hope this helps,
Shelley
[Posted in FML issue 4132]