If the longer nights mean it is harder and harder for you to stay in your workout routine, consider asking a friend for help.
Researchers at the University of Pennsylvania School of Medicine found that people who went to fitness classes frequently and lost weight inspired their workout buddy to do the same.
If you do not have a like-minded friend you can ask to workout with you and hold you accountable, consider joining one of the walking, hiking or other fitness groups on Meetup.com. If you belong to a gym, ask a trainer if they know anyone in search of a workout partner. You could also ask a co-worker or two to start a lunchtime walking group.