Hummingbirds will visit a feeder all summer long, once they get the idea that it’s filled with nectar. You can buy packets of nectar mix, but making your own is easy and inexpensive.
Mix 1 part white sugar (not honey, which hosts hummer-harming bacteria) with 4 parts water. Boil the mix, and let it cool before filling the feeder. Once hummers start coming, decrease the solution to about 1 part sugar and 8 parts water. No, this isn’t the old bait-and-switch tactic—there’s a good reason for diluting the solution. Hummingbirds can sometimes suffer a fatal liver disorder if they get too much sugar. Replace the nectar every other day in warm weather.