Diane and I have been feeding year round for over a decade in Mont County.  We offer black oil sunflower and niger seed, suet, and hummer nectar during the summer months.  We add white millet through the winter.
We have constant activity no matter what the month. The species mix changes with the seasons, of course.  
Yesterday I had a lunch hour at home and watched out the windows as I ate.  Twelve species dropped in: House Finch, Goldfinch, Cardinal, Chickadee, Titmouse, W-B Nuthatch, Downy, House Wren, Robin, Mourning Dove, Blue Jay, and Ruby-throated Hummer.
Nice having lunch with old friends!