Not very specific but you will find early color in late August to mid-Sept (individual leaves to branches and an occasional whole tree showing fall colors). BUT! this tree may be in a sea of green. You rarely will see much more than that until mid-September.
Then as the September continues, the color will continue to flow south from Canada into Vermont, New Hampshire and Maine.
By Mid-October Massachusetts should be turning nicely and by mid to late Oct the coastal areas of MA, RI and CT are or should be turning brightly.
but people call me Jeff Foliage.
I have several pages that I write blogs for such as: http://www.4cornersnewengland.com/
My most popular blog is for Leaf peepers: Jeff Foliage.com.
I live in Salem, Massachusetts and work as a blogger and Travel Photographer. I'm also the founder of the New England Photography Guild.
Feel free to visit me on my blogs and see what life in New England is like.
I started with Yankee Magazine as their first blogger on everything fall foliage. Now I blog on my own blog on my favorite subject, telling leaf peepers where the fall foliage is showing up in New England and helping them (to some extent) plan their fall foliage vacations.