Boston is a great destination for tourists and photographers alike. The largest city north of New York City on the East coast of the United States of America offers so many sites to explore and there is really no best time to visit. New England is famous for its abundant fall foliage season and autumn with its vibrant colors is one of my most favorite times of the year. I look forward to it year-round and it is way to short. Autumn in Boston is particular special as the historic sites and city skyline is submerged into a carpet of colorful and plentiful colors of fall. Hope you had the chance to experience fall foliage in Boston and New England at some point or you have plans to do so - I am sure its worth a visit!
Good light and happy photo making!