One of the most commonly used ways to forecast changes in the weather is the change in atmospheric pressure. This is because weather patterns are carried around in regions of high and low pressure. Thus, a slowly rising atmospheric pressure over a week or two usually indicates settled weather that will last for a long time. When atmospheric pressure suddenly drops over a few hours, a storm which will not last long but with heavy rains and strong winds is approaching.

Barometers are widely used as an instrument to measure atmospheric pressure. Its two main types are the older but reliable Mercury barometers and the newer digital friendly Anervia barometer. Weather stations typically use a digital barometer that uses electric charges to measure air pressure to produce more accurate weather forecasts.