Barometric pressure · Very low
28.54 inHg.
28.54 inHg is 1.38 inHg below standard — deep-storm pressure. Here is what the reading means, what it means rising, steady and falling, and how it converts across every scale your instruments might use.
Very low
1.38 inHg below the 29.92 inHg standard
what this reading means
A powerful, fully developed low-pressure center is at or very near the station. Air is converging at the surface and rising through a deep layer of the atmosphere, which is why storms at this pressure produce rain over a wide area rather than in isolated cells.
Heavy, persistent precipitation and strong wind across a broad footprint. On the US East Coast this is classic nor easter territory; in the Gulf and Atlantic it is a landfalling tropical system; in the Midwest it can be an inland cyclone strong enough to produce a wind event without a thunderstorm.
the number is half the signal
A barometer reading on its own is a snapshot of a system in motion. Forecasters read the tendency — which direction the value has moved over the last three hours — because that is what distinguishes weather arriving from weather leaving. The same 28.54 inHg carries three different forecasts.
Rising to 28.54 inHg
The center has passed or is filling. Expect the wind to shift direction as the low moves off, then gradually ease. Clearing usually lags the pressure rise by several hours.
Steady to 28.54 inHg
The storm is neither strengthening nor weakening, and it is not moving quickly. A stalled deep low is how a wind and rain event turns into a flooding event.
Falling to 28.54 inHg
Continued deepening. A drop of more than 0.07 inHg (2.5 hPa) in three hours at this level indicates a storm still organizing, and the peak wind has not arrived yet.
how fast it is moving
Rate matters more than direction. Weather services report pressure tendency over a three-hour window, and these are the thresholds that change what a forecaster says:
28.54 inHg in every scale
All five of these are the same pressure. US weather apps default to inches of mercury, a holdover from seventeenth-century mercury-column barometers; almost everywhere else uses hectopascals, and aviation and marine instruments often use millibars, which are numerically identical to hPa.
28.54 inHg
inches of mercury — US weather apps
966.5 hPa
hectopascals — the international standard
966.5 mb
millibars — numerically identical to hPa
724.9 mmHg
millimetres of mercury
96.65 kPa
kilopascals
why your altitude does not change this number
The pressure your weather app shows is sea-level adjusted — the value your station would read if it were at sea level. It has to be, or the map would be useless: real station pressure in Denver runs near 24.8 inHg simply because there is a mile less atmosphere overhead, and every mountain station would look like a permanent hurricane.
So 28.54 inHg means the same thing in Denver as it does in Miami. If you own a barometer that reads noticeably lower than your weather app, it is almost certainly reporting raw station pressure and needs to be set to your elevation.
where this sits on the scale
The lowest non-tropical pressure ever recorded in the continental United States was 955.2 hPa (28.21 inHg), over Minnesota on 26 October 2010 — so a reading in this band sits within striking distance of the strongest storms the continent produces.
Rare. Most US stations see pressure this low only during a named storm or a once-in-several-years extratropical cyclone.
pressure and how you feel
Headaches, migraines, and aching joints are widely reported around pressure changes, and the research finds a real but inconsistent association — most often with falling pressure rather than with any particular value. A barometer sitting steadily at 28.54 inHg is a much less likely trigger than a fast drop toward it.
If your symptoms genuinely track the weather, the number to watch is the three-hour change, not the level. This is general information about atmospheric pressure, not medical advice.
nearby readings
For the physics underneath all of this — why rising pressure suppresses cloud and falling pressure builds it — read barometric pressure explained, or see how to read a surface pressure map. The full index of readings is at the pressure reference.
What does a barometric pressure of 28.54 inHg mean?
28.54 inHg (966.5 hPa) is 1.38 inHg below the standard 29.92 inHg, which classifies as very low — deep-storm pressure. On its own the number is only half the signal: the band tells you the regime, and the direction of change tells you the forecast. Rising, it means the center has passed or is filling. Falling, it means continued deepening.
Frequently Asked Questions
Is 28.54 inHg high or low barometric pressure?
28.54 inHg is below standard, by 1.38 inHg. Standard sea-level pressure is 29.92 inHg or 1013.25 hPa, and meteorologically this reading falls in the very low band — deep-storm pressure. Rare. Most US stations see pressure this low only during a named storm or a once-in-several-years extratropical cyclone.
What is 28.54 inHg in hPa?
28.54 inHg equals 966.5 hPa. The two scales measure the same thing: 1 inHg is 33.8639 hPa, so to convert inHg to hPa multiply by 33.8639, and to convert hPa to inHg multiply by 0.02953. The same reading is also 724.9 mmHg and 96.65 kPa.
What weather comes with 28.54 inHg?
Heavy, persistent precipitation and strong wind across a broad footprint. On the US East Coast this is classic nor easter territory; in the Gulf and Atlantic it is a landfalling tropical system; in the Midwest it can be an inland cyclone strong enough to produce a wind event without a thunderstorm. But the reading alone will not give you a forecast — the tendency will. Continued deepening. A drop of more than 0.07 inHg (2.5 hPa) in three hours at this level indicates a storm still organizing, and the peak wind has not arrived yet.
Does 28.54 inHg cause headaches?
Many people report headaches, migraines, and joint pain around pressure changes, and the research finds a real but inconsistent association — most often with falling pressure rather than with any particular value. A steady reading of 28.54 inHg is far less likely to be the trigger than a rapid drop toward it. If symptoms track your barometer, the rate of change is the number to watch, not the level.
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