* Fog. Fog is a cloud that forms near the ground when water vapor condenses on tiny particles in the air. Fog is most common in the early morning and evening, when the air is cool and humid.
* Clouds. Clouds are formed when water vapor condenses on tiny particles in the atmosphere. Clouds can take many different shapes and sizes, depending on the temperature and humidity of the air.
* Rain. Rain is water that falls from the sky when water vapor condenses into droplets that become too heavy to stay suspended in the air. Rain is most common in the tropics, where the air is warm and humid.
* Snow. Snow is water vapor that condenses directly into ice crystals. Snow is most common in cold climates, where the air is cold and dry.
* Sleet. Sleet is a mixture of rain and snow that occurs when the temperature of the air is near freezing.
* Hail. Hail is balls of ice that form when raindrops freeze inside clouds. Hail is most common in the summer, when the air is warm and humid.
