The number of visitors and the rates for lodging reach their peaks along with the color of the leaves during foliage season, from late September to mid-October. But if you have never seen a kaleidoscope of autumn colors, it is worth braving the slow-moving traffic and paying the extra money. In summer the state is lush and green. Winter, of course, is high season at Vermont's ski resorts. Rates are lowest in late spring and November, although many properties close during these times.