A 1 cubic kilometer (km3) cloud contains 1 billion cubic meters. Doing the math: 1,000,000,000 x 0.5 = 500,000,000 grams of water droplets in our cloud. That is about 500,000 kilograms or 1.1 million pounds (about 551 tons).
What does a typical cloud weigh?
A typical cloud has a volume of around 1km3 and a density of around 1.003kg per m3 – about 0.4 per cent lower than that of the surrounding air, which is why they float. So cranking through the maths, that means that a typical cloud weighs around a million tonnes.
Can you sit on a cloud?
Nope. You can't sit on a cloud, because there's really nothing there. What you think of as a cloud is basically just air. It looks the way it looks because there are many, many, many tiny droplets of water suspended in the air, which refract the light and make them look white (or gray, depending on conditions).