I’ve found that the too cold and wet is no factor. If it is still wet out, then it isn’t too cold. When it is cold, wet is now solid. So there is that. When you’re below -teens and the wind is above 20 or so knots, I usually keep it short ~30-40 mins. As for just wet …depends. Some trails here you can ride when wet, the leader and community ride when it is wet and we all pitch in to keep it up. However, I usually look to hit some urban action because cleaning mud is not something that I enjoy. Although, I will admit that the 2 thunderstorms that I have been caught in were 2 of my most fun rides. However, when it’s really nasty out, that is my reason to get some up-keep done around the house.