Barometer and Weather

Changes in atmospheric pressure are one of the most commonly used ways to forecast short-term changes in weather. In order to observe these changes, an instrument known as a barograph is used. A barograph provides a continuous trace of the variations in air pressure over time, which is called the air pressure tendency. A typical rule of thumb when using pressure to forecast the weather is: Rising air pressure usually means continued fair or clearing weather. Falling air pressure is a general indication that the weather is changing and can signal the approach of stormy conditions.