Mildly lowered temps are no problem. But wood gets appreciably stiffer when the temperature drops below freezing, enough so that marginal backs may blow from the extra tension strain (been there). Repeated freezing and thawing, as in a shed or similar unheated space over the winter here is actually harmful to wood, lowering it's compression strength permanently. Living above 60th parallel north makes these issues a reality.
Tuukka
