The Hummzinger from Aspects, Inc. and similar hummingbird and oriole feeders are the easiest to clean and fill, but in rain are liable to fill with water.
Commercial rain shields made for bird feeders (also touted as squirrel guards) can be expensive.
At a local restaurant supply store I found a functional substitute: a plastic salad bowl for about two dollars. These are manufactured of PET plastic in various sizes; the example below has a fluid capacity of 160 ounces and a maximum diameter of 12 inches.
Any similarly shaped plastic bowl will do but these, besides being inexpensive, are very lightweight and easily replaced.
You could, instead, use one of the covers which package supermarket cakes or frozen pies (of those, the Claim Jumper Lemon Meringue is a particularly good choice due to its size and depth). However, the bowls offer a few advantages. They tend to be a little deeper and provide better coverage by compensating for the length of the feeder's hanger. And, being more aerodynamic, they appear to be more stable in the wind and rain.
After a bit of experimentation, I came up with the design shown below from parts found in my garage. It takes only a few minutes to assemble.
1 Plastic Salad Bowl (At least 12 inches diameter)
2 Screw Eyes
2 Fender Washers
1 S-Hook
1 wooden dowel -- 1/2 inch diameter, two inches long
The CG image to the right shows the parts and assembly order.
Mark the center of the bowl's base and punch a small hole for the lower screw eye. With cutting the length of dowel and drilling pilot holes in it for the screw eyes, that's about all the tool use in assembling this design.
UPDATE: Since completing this page, I found a similar design at a recycling blog, using the same type plastic salad bowl. Her approach is to use parts cut from a two-liter water bottle and a chip clip, takes a bit more labor and some glue, but is worth checking out as an alternative.
I hope this information is useful. Any constructive comments or suggestions would be welcomed.This page uses the optional Paddington font.