Katherine Mansfield/Observer-Reporter 3 / 6 Peak season for leaf-peeping this year is in October. The report will be posted every Thursday during peak foliage season. For most of the nation, peak fall color arrives in October, with Pennsylvania typically at its peak late in the month, although the leaves are starting to change colors already. What I’m hearing at some of the highest elevations is that maybe the first week of October for peak fall foliage. Marshall said the recent span of cooler nights should result in an earlier peak season for the fall foliage.