When it’s so cold outside you can see your breath, what you are seeing is actually a little cloud. When steam rises from a kettle of boiling water, it’s a cloud you’re seeing. When the fog rolls in, you guessed it—it’s a cloud.
The air around us is filled with moisture that it soaks up from oceans, lakes, and rivers. As air rises from the warmth of the ground and meets cooler air above, its temperature falls. This causes the moisture to form microscopic droplets of water (the process is called condensation). Clouds are made up of millions of these tiny droplets.