The best time to view fall foliage depends on latitude and geographic region but generally runs from late September to late October. In the Northeast, the leaves begin changing around the time of the autumnal equinox in the northwestern regions of New York, Vermont, New Hampshire and Maine.
Peak foliage times proceed in a southeasterly direction, reaching central and upstate New York, Vermont, New Hampshire and Maine by the first and second weeks of October and reaching central and northern Massachusetts by this time. The middle of the second week of October usually sees the greatest portions of New England, New York, Pennsylvania and the Great Lakes regions at their peak. Foliage viewing usually ends with the peak viewing ending in the southeastern portions of the Northeast by the third week of October.
The timing, colors and intensity of the foliage vary from year to year and depend on several climatic factors, such as rainfall, average temperatures and windstorms, and blight or insect infestations, which may prematurely strip many trees of their leaves some years.