A high pressure system is a weather phenomenon characterized by higher atmospheric pressure compared to surrounding areas. These systems typically bring clear skies and calm weather, as they inhibit cloud formation and precipitation. The air in a high pressure system descends, which warms it and reduces humidity, leading to stable conditions. High pressure systems often move slowly and can influence weather patterns over large regions. They are commonly associated with fair weather, but can also lead to temperature inversions, where warmer air traps cooler air near the ground. This can result in fog or air quality issues in urban areas.