Depends. Letchworth will probably peak a week later; been there during the Fall years ago and it seemed like mid~October was a good bet.
One thing to consider~valleys and gorges trap cold air at night. As I recall the gorge, at Letchworth and the gorge in the city, would peak about a week before the flatlands around both gorges. So looking around the general area this time of year won't indicate what's going on down in both gorges.