The weather on planet Earth changes constantly. One reason is because the winds are always shifting, rising, falling and creating areas of various pressure in the atmosphere. A high-pressure system is one of these results of the shifting winds.

A high-pressure system means the pressure inside the system is higher than that of the surrounding areas. The high-pressure system is usually associated with fair weather. This is because as the air sinks, it warms and is able to hold more water vapor. Thus, in a high-pressure system, clouds tend to evaporate and the air stabilizes. Storms have a hard time forming in stable air.

The humidity is usually lower in or near a high-pressure system, also contributing to fair weather. Many desert areas of the world are associated with a persistent high-pressure system climate. The drier air helps create the desert environment.

Although most people like the weather that comes with a high-pressure system, it isn’t all good. Heat waves and drought conditions come about because of several high-pressure systems moving through an area, or because of a prolonged system that will not move out of an area. In fact, meteorologists hypothesize that the Dust Bowl of 1930s America, with its droughts and heat, was caused by a persistent high-pressure system trend across the Midwest and through Arkansas and Oklahoma.

Sometimes, a particular area will become associated with a high-pressure system. In the summer, those living in the Southeastern U.S. are familiar with the Bermuda High phenomenon. This is a high-pressure system that tends to be long-lived, contributing to the summer heat. The clockwise windflow around a high-pressure system also ensures the moisture coming from the Gulf of Mexico moves across the area, creating the high humidity for which the area is infamous.

A high-pressure system can also cool the weather, as well. Those in the United States are also familiar with the winter Siberian Express and Alberta Clipper high-pressure systems that bring in Arctic or Canadian cool air and cause cold snaps. The high-pressure system, in conjunction with the low-pressure system, are part of the complex climatological machine that drives weather on Earth.