I live in Alberta where the winters are COLD! We have been having a lot of -20 or -30 C temps lately and I was wondering how cold is too cold to ride. If its under -10 I usually don't ride with a bit in the horse's mouth, as I don't want to put a frosty, freezing bit in it's mouth and I just ride with a halter and lead ropes. I generally don't ride under -20 either - just too cold for me but do you think it does any harm to the horse? I don't do anything faster than light trotting either in the winter typically, so its not like they are working very hard.