I am sure that I am not the only one that feeds the hummingbirds, so you may have the same problem as me. None of the feeders are protected in the rain. I don't have a protected place to hang mine, and it hangs on a shepherd's hook outside my kitchen window. But when it rains, the rain runs into the feeding tubes and dilutes the nectar.
So I have come up with a solution. I cut a circle a little bit smaller than a Styrofoam picnic plate and made a hole in it to string the wire through. Then turn the plate upside down and glue it to the circle. The plate is just enough to keep the rain out of the feeder.
In my pictures you will see that I have used a 1/2 inch plywood circle under my plate, but that is only because I am a woodworker and it was handy. The flap from a cardboard box will do just as well. It just takes a little something to keep the plate from flopping in the breeze.
Good idea, now if I could only get hummingbirds to stick around! They hate me I think!
It takes years to build up a good resident or returning group of hummers. Start with some attractive plants and at least two feeders. For example, here on the west coast, Anna's hummingbirds are attracted to eucalyptus, so I planted one, and within a couple weeks had my first.