Connie has a valid point about the uniformity of the damage to the leaves. If both new and old look like this then I agree that you should favor a virus. If a section of the plant is damaged only then this would be frost/rain/botrytis. The photos here show weather damage on a couple of my lilies. Are yours Asiatics, Cody? How long have they been in your garden? Certainly, anything with L. longiflorum in its genetics (e.g. LA hybrids) could be prone to virus. In my experience they are weather-susceptible too.
