“On cloud nine” is said to have come from references long ago (like a hundred years ago) to the number nine cloud in meteorological descriptions. Cloud number nine was the big puffy one. Here’s a picture of a rare cloud formation just formed over Antarctica. Clouds like these take temperatures of less than mins 172 F. I guess it was minus 189 in the stratosphere where these clouds formed. The pearly coloring is their hallmark. Pearly lining beats silver lining, methinks.