Hello how may I help you? I have a really random question Sure, what do you want to know? I want to know about the biggest cloud on record Biggest in what way? Tallest? Widest? Heaviest? Hmm. Tallest then the widest. Do you mean the highest clouds in the atmosphere or the clouds which are themselves the tallest? Clouds which are the tallest overall Cumulonimbus clouds are the tallest overall. How tall? They can range up to 50,000 feet. thanks