What Barometers Measure
Comparing Barometer Changes
Once you know what the average atmospheric pressure should be, following weather is one step closer. Barometers measure pressure in several units, usually inches or millibars. For the sake of efficient demonstration, let's assume the average pressure of a given area is 29 inches. Here's what can happen to that barometer reading:
- No Change: If that reading stays at or very near 29 inches, that means the weather in the area is stable. No changes are occurring.
- Increase: As the pressure increases, air is becoming heavier and more stable. When barometer readings go above 29 inches, weather generally gets warmer, even muggier. Because the air mass is not going anywhere, urban areas may experience smog.
- Decrease: Conversely, as barometer readings fall, fast-moving low pressure air is coming in. Usually associated with winds and storms, low barometers tell a definite change is on the way.
Some barometers have weather indications inscribed on the meter face. This excellent tool for explaining readings make barometers more accessible to the general public.
Keep in mind that there are exceptions to reading barometers. Develop skills through daily comparisons of barometer readings and observed weather. Keep a log of barometer readings and refer to it frequently. Over time, experience in forecasting weather can make anyone a decent amateur (perhaps professional) meteorologist.
For more helpful information on all things weather, browse through WeatherInstruments.com for some great insight into a wonderful hobby.