How does fog form?

Fog forms when water vapor condenses into tiny water droplets or ice crystals near the Earth's surface. This happens when: 1. **Air cools:** Reaching its dew point, causing condensation. 2. **Moisture increases:** Raising the dew point closer to the air temperature. Common causes include radiative cooling of the ground on clear nights, advection of warm, moist air over a cold surface, and mixing of air masses with different temperatures and humidity levels.