Not at all. Check the sunrise calendar: http://www.sunrisesunset.com/custom_srss_calendar.asp
There's plenty of usable light through September. Your plant(s) will finish late in the season, but they'll finish as long as it doesn't get too cold and rainy.
I dont know if it would be worth it to ya, Im in so cali and mine are 6 feet tall and pre flowering. I suspose you could get a few small ones come harvest time.