FOG is a weather phenomenon that occurs when tiny water droplets or ice crystals are suspended in the air near the ground. It reduces visibility, making it difficult to see objects clearly. FOG typically forms when warm, moist air cools and condenses, often during the night or early morning. There are different types of FOG, including radiation fog, which forms on clear nights, and advection fog, which occurs when warm, moist air moves over cooler surfaces. FOG can impact travel and safety, especially for drivers and pilots, as it can create hazardous conditions on roads and in the air.