How to prevent shifting issues due to derailleur or cables freezing in cold weather It's been fluctating in temperature between 0F and 20F in my area. I've been riding my 1x9 geared mountain bike to and from work. However, due to the cold weather, I'm having issues shifting. 

It seems that I can typically shift in to an larger cog, but my derailleur is unresponsive when I shift to a smaller cog. I think this is because when shifting to a larger cog, the cable is pulled by the shifter, however for the smaller cog, the derailleur would be moved back by spring pressure and due to the cold conditions, it's not strong enough to fight the frozen gunk.

What can I do to keep my bike shifting in the cold?
Clean and dry (hair-dryer) the derailleur. Relube. Check. If necessary take out the cables, chase the water from the housings by pressing thin oil with a syringe. Put the cables back in or replace with new ones. It's always a good idea to change the cables before winter if you've been riding through rain in the good season. And change them again at the beginning of the good season!