I'll close today with a selection of photos of Clouds of the Month, from the website of the incomparable Cloud Appreciation Society. Their Cloudspotter's Guide is an excellent book.
Top to bottom:
When Cirrus clouds are arranged like the backbone of a fish, they are given the name ‘vertebratus.’ (Photograph © Tim Middleton).
...a display of cloud iridescence. This colourful optical effect is caused by sunlight being diffracted as it passes around the cloud particles. (© Photograph Andrew Kirk)
Mount Rainier’s shadow being cast onto the clouds above (Photograph © Nick Lippert)