Humidity refers to the amount of water vapor in the air, measured as a percentage. Dew point is the temperature at which water vapor condenses to liquid or solid form, causing clouds to form. Different types of precipitation, like rain, snow, or hail occur when water droplets in clouds become too large for the clouds to support and fall to the earth's surface. There are three main types of clouds - cirrus, cumulus, and stratus - which form at different levels in the atmosphere and under varying weather conditions.