Extending your season depends on how early or late you plan on riding. Here's a sunrise/sunset table for anywhere on the planet. For your area, Boston, the sun rises at 610 and sets at 1918 (6:10 am and 7:18 p.m.) on September 1. That's not too bad if you are commuting. However by the end of October (before the time change), you'll be looking at the sun rising at 710 and setting at 1745. After the time change, you'll be looking at the sun rise at 610 but setting at 1645. Most people who get squished on bikes, do so at night and the evening hours are probably worse then morning for riding in the dark. Plan accordingly.