I've heard it can be caused by one-handed powerslides
Seriously though, strange that it happened to both at once......have you followed a dump truck full of sand recently?
As for the cold, If temperatures where you are (lows in the mid-20's F I'm guessing?) caused it I think we'd be hearing about it a lot more.
I can see a situation where extreme cold could cause the fork tube to shrink more than the seal can compensate for, but I have no idea what the thermal properties of either the tube or the seal are so it's total conjecture.
Look at the bright side, leaking fork seals are better than leaking cases, strange engine noises, and lots of other problems we've all faced over the years!