There is a meteorological "cloud 9," but the cloud nine we refer to when someone is in a really good mood may not be that cloud.
The initial edition of the International Cloud Atlas was published in 1896. This was the first all-inclusive meteorological guidebook and had its own cloud classification system which gave numbers to clouds according to their altitude. The highest clouds given the number "0" while fog was considered a "10." The "9" category included any cloud below 50,000 feet that was still high enough not to be considered fog. Today we call these thunderstorm-causing formations cumulonimbus clouds. At some point the US Weather Bureau used its own number classification system, with a cloud nine being a high cumulonimbus cloud anywhere from 30,000 to 40,000 feet above sea level.
What does this have to do with being "on cloud nine?" No one is quite sure. Like many phrases the history of the cloud is somewhat obscure and no solid connection can be made between the weather classification and the saying. What we do know is that the first numbered cloud was cloud seven, referring to the Judaic seventh heaven where God commands the angels and watches over the souls of the righteous. In the 1930's someone who was on "cloud 8" was drunk to the point of being giddy. Finally, cloud 9 was first recorded shortly after WWII, originating in the U.S. and eventually made its way to Canada and Britain. The number nine is a lucky number and shows up in other sayings like "nine lives" and "the whole nine yards."
So, there are three possible sources for the name:
A new set of people would have been working with meteorological data during the war to plan battles and may have used "Cloud Nine" to refer to someone above the storm.
Cloud Nine refers to a happiness beyond the drunkenness of cloud eight.
The nine was used as it was considered lucky referring back to either cloud seven or cloud eight.
Posted 3526 day ago