A front is a boundary that separates two different air masses in the atmosphere. These air masses can vary in temperature and humidity, leading to various weather conditions. When a warm air mass meets a cold air mass, it can create a warm front, while a cold front occurs when a cold air mass pushes into a warmer area. Fronts are essential in meteorology because they help predict weather changes. For example, when a cold front approaches, it often brings storms and cooler temperatures, while a warm front may lead to gradual warming and precipitation. Understanding fronts helps forecasters provide accurate weather predictions.