Paul;
It seems as well as dehydration, a number of hippys here with BHR's (Babybarista, Woodstock Hippy, James Laveglia [see his hip story under Dr Brooks]) as well as myself have reported that colder temps seem to also be (anecdotally) correlated to squeaking. Mine was after doing a lot of work outside in colder temps last spring, Woody just reported squeaking after being outside working all day this spring, Barista after walking along a cold beach out in the pacific NW, and James Laveglia after mushroom hunting in Michigan in colder temps... (search squeak or squeakapalooza here).
In none of these reports here did anyone report adverse impact, just the noise. I wonder about synovial fluid viscosity in colder temps and with the added dimension of dehydration as the cause.
For me it was hilarious, but I was not able to get my wife to witness until the second time it happened last spring, to share the mirth.
Best regards,
Dan