Heavy

Clouds are made up of water and water has quite a substantial weight. The only reason clouds float, is because they are less dense than dry air. The actual weight of a cloud is 0.5 grams per cubic meter. This quickly becomes scary once you realize how absurdly massive clouds are. On average, clouds easily reach a size of 1km x 1km. That's 1000 × 1000 × 1000 × 0.5 grams of weight or 500,000 kg of weight.