What is normal barometric pressure?

Standard sea-level pressure is 29.92 inches of mercury (inHg), or 1013.25 millibars (mb) / hectopascals (hPa). The U.S. typically reports inches of mercury; the rest of the world and meteorologists use millibars.

Does low pressure mean bad weather?

Usually, yes. A low-pressure system is rising air that cools, condenses, and produces clouds, precipitation, and storms. A high-pressure system is sinking air that suppresses clouds and brings fair, settled weather.

What does falling barometric pressure mean?

A falling barometer means a low-pressure system or front is approaching and unsettled or stormy weather is likely. The faster the pressure drops, the more vigorous the incoming system tends to be — a rapid fall is the classic "storm coming" signal.

What Is Barometric Pressure? — Reading the Barometer

What Is Barometric Pressure? — Reading the BarometerBarometric pressure is the weight of the air overhead — the best single signal of a weather change. Falling pressure means a storm is approaching; rising means fair weather. Units, highs vs lows, and reading the trend.Barometric pressure (atmospheric pressure) is the weight of all the air in the column above you, pressing down. It is the single most useful number for anticipating a change in the weather: falling pressure means a storm system is approaching, while rising pressure signals clearing and fair weather. The direction it is trending matters more than the raw value.The unitsIn the U.S. pressure is usually given in inches of mercury (inHg) — standard sea-level pressure is 29.92 inHg. Meteorologists and the rest of the world use millibars (mb) or hectopascals (hPa); standard sea-level pressure is 1013.25 mb.Highs vs lowsA high-pressure system is sinking air — it suppresses clouds and brings fair, settled weather. A low-pressure system is rising air — it cools, condenses, and produces clouds, precipitation, and storms.Reading the trendA rapid pressure drop ahead of a front is the classic "storm coming" signal. The faster it falls, the more vigorous the approaching system tends to be. Pressure is mapped as isobars — the contour lines on a surface analysis chart; tightly packed isobars mean a strong pressure gradient and stronger wind.

Frequently asked questions

What is barometric pressure?: Barometric (atmospheric) pressure is the weight of the entire column of air above you pressing down. It is one of the most useful numbers for anticipating a weather change: falling pressure signals an approaching storm system, while rising pressure signals clearing, fair weather.
What is normal barometric pressure?: Standard sea-level pressure is 29.92 inches of mercury (inHg), or 1013.25 millibars (mb) / hectopascals (hPa). The U.S. typically reports inches of mercury; the rest of the world and meteorologists use millibars.
Does low pressure mean bad weather?: Usually, yes. A low-pressure system is rising air that cools, condenses, and produces clouds, precipitation, and storms. A high-pressure system is sinking air that suppresses clouds and brings fair, settled weather.
What does falling barometric pressure mean?: A falling barometer means a low-pressure system or front is approaching and unsettled or stormy weather is likely. The faster the pressure drops, the more vigorous the incoming system tends to be — a rapid fall is the classic "storm coming" signal.

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