Air pressure is the force exerted by the weight of air above a specific point. It is measured in units like pascals or millibars and varies with altitude; as you go higher, there is less air above you, resulting in lower pressure. This pressure affects weather patterns and can influence how we feel. For example, when high pressure systems dominate, the weather tends to be clear and calm, while low pressure systems can lead to clouds and precipitation. Understanding air pressure helps meteorologists predict weather changes.