What goes up must come down? Not exactly how barometric pressure works but it is a good starting point to understanding barometric pressure and how it affects our surroundings. So what is it?  A barometer measures the air pressure in the environment. You may hear meteorologists talk about barometric pressure in their forecasts because they use it as predictor for future weather patterns. For example, low-pressure weather systems usually lead to cloudiness, wind, and precipitation. High-pressure systems usually lead to fair, calm weather. * Air temperature and altitude impact barometric pressure.

High Barometric Pressure

When the barometric pressure is high, temperature conditions tend to be more comfortable as the amount of oxygen in the air is stable. As air higher in the atmosphere falls, it warms and expands. The expansion of the air in the falling air mass tends to lower its humidity, which reduces or prevents the formation of clouds. Because of this effect, areas of high pressure often have clear, dry weather.**

Low Barometric Pressure

The higher the altitude, the lower the atmospheric pressure, which means the amount of oxygen in the air decreases. That is what mountain climbers need to be careful of the altitude because it will impede their ability to breath easier due to the lack of oxygen. Low barometric pressure actually means the air pressure is rising.