Here are some useful tips about interpreting a barometer. Note that decreasing barometric pressure indicates storms, rain or windy weather whereas rising barometric pressure indicates good, dry, and colder weather. A quick drop in pressure over a short time may indicate a storm in 5 to 6 hours. Large steady sustained episodes of decreasing pressure forecasts a long period of poor weather. The poor weather will be worse if the pressure started rising before it began to drop. A rapid elevation in pressure, during fair weather may indicate a low pressure zone is approaching. The pressure then may decrease forecasting poorer weather. Rapidly  rising pressure, with initially low pressure, indicates a short period of fair weather is likely. A large, slow and sustained rise in pressure suggests a long period of good weather is heading your way!