Hello how may I help you? I was wondering what the biggest cloud that was ever recorded was? I can help with that information, but I need some clarification. By biggest, did you mean tallest, widest or heaviest? I mean widest. The widest cloud to ever exist was seen in the Amazon River in 1995. What about the tallest cloud? The tallest cloud is the Noctilucent cloud. What is the heaviest cloud? The heaviest cloud is the Tsar Bomba. That's some interesting facts about clouds. Thank you! I'm glad I could help!