Wet Bird Food

Does anyone have any ways of waterproofing their bird feeders? I have sunflower heart feeders, peanuts, seed, etc., and obviously when it rains, they all get soaked then the birds generally don't use them. Costs a small fortune just to throw it all away. Then, refill, it inevitably rains again, then same thing again.

Difficult I suppose because it rains a lot in the winter when birds need food the most!

What's people's experiences? Thoughts?