Do you have a photo? Powdery mildew is fairly common if you've been wet or have poor air circulation.

Other light spots can be any number of diseases or sunburn, but 'white' makes me think mildew.

Definitely not mildew. Mildew wipes off. These are part of the leaves, rather than on the leaves.

Here're some photos:

{{gwi:645864}}

{{gwi:645867}}

You're right: that's not powdery mildew. I don't have any other guesses, but it doesn't look too devastating to either the plant or the eye.

That's because the photo was taken back in June. The leaves are now covered with the white spots. It was the best photo I had at the time. With the heavy rains, I couldn't go outside to take newer photos.

They do still bloom and grow, though. But still... I'd like to find out what that is in the even it is contagious.

Thanks!