Florida · 6 m elevation

Barometric Pressure in Miami, FL

• 30.03Average pressure (inHg, sea level)
• 19.8Swing days a year · 50th of 50
• 3.2Big-swing days a year (≥10 hPa)
• 6.9Significant 24h drop days a year

Overview

Miami has the steadiest barometer of 50 US cities: 19.8 significant swing days a year vs a national median of 180.7. Averages 30.03 inHg (1017.1 hPa).

Miami runs at a mean sea-level pressure of 30.03 inHg (1017.1 hPa), with 90% of hours falling between 29.87 inHg (1011.5 hPa) and 30.21 inHg (1023.0 hPa). What sets the city apart is not the level but the stillness. The standard deviation of pressure is 0.11 inHg (3.57 hPa), the lowest of the 50 cities in this dataset and about half the national median of 6.87 hPa. The typical 24-hour change is 0.04 inHg (1.2 hPa), and 95% of days move less than 0.14 inHg (4.6 hPa) — under the 6 hPa threshold that counts as a significant swing.

Across 87,672 hours from 2015 through 2024, Miami logged 19.8 significant swing days per year against a national median of 180.7 — roughly one-ninth as many. Big-swing days, where the 24-hour change reaches 10 hPa, average 3.2 per year versus a median of 86.1, a gap of nearly 27 times. Miami ranks #50 of 50 on swing days, #50 on big-swing days, and #50 on standard deviation. Denver, the most volatile city on the list, records 14 times Miami's swing days; Colorado Springs posts 54 times as many big-swing days. Even the next-calmest city, San Diego, sees 1.8 times Miami's swing total, and Florida neighbors Tampa and Jacksonville run 2.2 and 4.1 times higher.

At 6 meters elevation, Miami's station pressure averages 30.01 inHg (1016.4 hPa) against a sea-level-adjusted mean of 30.03 inHg (1017.1 hPa) — a difference of 0.02 inHg (0.7 hPa). A home barometer left on raw station pressure will read essentially the same as the sea-level figures quoted in forecasts, which is not true in higher cities.

Migraine & pressure-sensitivity outlook

• Low — under 6 hPa (0.18 inHg)
• Elevated — 6 to 10 hPa
• High — 10 hPa (0.30 inHg) or more
• Dashed outline = forecast (after today)

Association only. This calendar shows days when pressure changed — or is forecast to change — sharply over 24 hours, conditions associated with pressure sensitivity in some people. It is not a prediction of symptoms, not a diagnosis, and not medical advice. The 30 days of history are there so you can compare the days you actually felt something against what the barometer did. Talk to a clinician about headache or migraine management.

For people who track barometric pressure, Miami produces the fewest of the conditions many pressure-sensitive people report as triggers of any city in this dataset. It averages 19.8 significant swing days a year (a 24-hour change of 6 hPa or more) and just 6.9 drop days, when that change is a fall. The national medians are 180.7 swing days and 86.1 big-swing days, so Miami delivers roughly one-ninth the flagged days of a typical US city and one-twenty-seventh the big ones.

The calendar is heavily lopsided. January is the most active month with 4.7 swing days and 1.9 drop days, followed by December, February, and March. June through August is where the record goes quiet: July logged zero significant swing days over the ten-year period, and May, June, and August together average 0.6. If cool-season frontal passages are the pattern you notice, they arrive in a narrow window and are generally visible in the forecast days ahead rather than scattered unpredictably through the year.

The qualifier is the hurricane-season tail. A city this steady still spans 1.32 inHg (44.6 hPa) end to end, because tropical systems produce the one kind of pressure change the subtropical ridge does not suppress — the September 10, 2017 event fell 0.48 inHg (16.1 hPa) in 24 hours. Those are rare, at 3.2 big-swing days a year, but they are the sharpest changes the city sees. Set against Denver's 177.5 drop days or Boston's 151, Miami holds within a narrow band for most of the year, with what activity there is concentrated in winter fronts and the occasional late-summer tropical system.

Seasonal patterns

Almost all of Miami's pressure activity is packed into the cool season. January averages 4.7 significant swing days, December 3.7, February 3.6, and March 2.1 — together about 14 of the year's 19.8. From May through August the barometer is close to a flat line: 0.2 swing days in May, 0.3 in June, 0.1 in August, and 0.0 in July across the full ten-year record. Monthly variability tells the same story, with February the most active month at 0.12 inHg (4.09 hPa) standard deviation and July the quietest at 0.06 inHg (1.91 hPa).

The driver is straightforward. Cold fronts reach South Florida only during the cool months; in summer the subtropical ridge sits over the region and the day-to-day barometer is governed by the sea breeze and the diurnal cycle rather than by passing synoptic systems. Monthly means follow the seasonal march, peaking at 30.10 inHg (1019.4 hPa) in January and February and bottoming at 29.95 inHg (1014.2 hPa) in September.

The extremes span 1.32 inHg (44.6 hPa) end to end. The record high, 30.50 inHg (1032.9 hPa), was set on January 9, 2017. The record low, 29.18 inHg (988.3 hPa), came on September 10, 2017, at the peak of hurricane season, and the same event produced the sharpest 24-hour fall in the record: 0.48 inHg (16.1 hPa) ending at 2:00 p.m. that day. The other four largest drops all ended between late October and late January — 0.37 inHg (12.4 hPa) on October 29, 2017; 0.35 inHg (12.0 hPa) on December 17, 2023; 0.35 inHg (11.8 hPa) on February 22, 2017; and 0.35 inHg (11.7 hPa) on January 27, 2019. Miami's maximum drop ranks #49 of 50, ahead of only Phoenix, so even the tail of the distribution is short by national standards.

Month by month

Swing days: 24-hour change of at least 6 hPa (0.18 inHg). Drop days: 24-hour fall of at least 6 hPa. Averages per year, 2015–2024.

Records and extremes

Sharpest 24-hour drops, 2015–2024

Nearby cities

• Tampa, FL
• Jacksonville, FL
• Atlanta, GA
• Charlotte, NC
• New Orleans, LA
• Raleigh, NC

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