Clouds form when water vapor in the air cools and condenses around tiny particles like dust or pollen, creating visible droplets or ice crystals. Different cloud types signal different weather: fluffy cumulus clouds often mean fair weather, while tall, dark cumulonimbus clouds can bring thunderstorms.
Precipitation occurs when those water droplets or ice crystals grow heavy enough to fall from the clouds. Depending on the temperature of the air below, precipitation can fall as rain, snow, sleet, or hail.
Severe storms form when warm, moist air rises quickly and collides with cooler air, releasing enormous amounts of energy. Thunderstorms can produce lightning, heavy rain, and hail, while the most powerful storms, such as hurricanes and tornadoes, form under very specific conditions of heat, moisture, and spinning air currents.