Fog shows up when water vapor, or water in its gaseous form, condenses. During condensation, molecules of water vapor combine to make tiny liquid water droplets that hang in the air. The fog disappears when the air temperature balances out with the temperature of the ground, and the water particles disappear- this happens most commonly during the morning to late morning hours. Clouds are formed when the air contains as much water vapor (gas) as it can hold. This is called the saturation point, and it can be reached in two ways. First, moisture accumulates until it reaches the maximum amount the volume of air can hold. The other method reduces the temperature of the moisture-filled air, which in turn lowers the amount of moisture it can contain.