It's said that no two snowflakes are alike. I'm not sure how this can be claimed unless someone's checking and comparing all the snowflakes, but I think a similar claim can be made for skies (unless of course they're perfectly blue without a trace of a cloud). As I was outside in the early evening I was reminded of a photo of cloud formations I took two weeks ago, and I decided to try to take a photo of generally the same area, but with a completely different sky. Take a look at the Day 60 (Mar. 1) photo and compare to this one. Now, two sky comparisons don't prove my point, but I think He provides endless variation for His glory and our enjoyment, as He does throughout His creation.
(18-55mm f8 1/400 sec ISO200)