It depends on whether you prefer winter or summer. In the winter time, January is a fantastic month to visit. The snow conditions are usually excellent and the Christmas crowd has gone home. In the summer, June is the time for wild flowers and other spring blooms. And then mid-September is fantastic for seeing the changing colors of the trees. As far as a time when you shouldn't visit Vail Valley, you should be aware that Christmas week is the busiest single week of the year, prices are going to be at their highest, and crowds will be at their largest.
