Barometric pressure in Seattle
Beneath its daily wave, pressure has risen slowly. It stands 3 hPa higher than it did at this time yesterday. The rise has eased: it holds near this level, then starts falling this morning.
Sea level reading, as of 08:00 local time.
The past week and the days ahead
The shaded part shows the days already gone. The thicker line is the forecast. The thin grey line is the average over a whole day, so you can see where pressure is heading under the daily up and down.
The week ahead
Each day at a glance: how far pressure moves, and the low and high it reaches.
Edges up slowly through the day.
24° / 16°low 1018 · high 1021 hPa
Falls steadily through the day.
25° / 14°low 1014 · high 1019 hPa
Edges up slowly through the day.
30° / 16°low 1014 · high 1018 hPa
Eases down slowly through the day.
26° / 15°low 1015 · high 1018 hPa
Barely moves all day.
23° / 15°low 1015 · high 1018 hPa
Edges up slowly through the day.
23° / 15°1.8 mmlow 1017 · high 1020 hPa
Eases down slowly through the day.
22° / 14°low 1018 · high 1021 hPa
Hour by hour
| Hour | Weather and temperature | Rain (mm) | Pressure (hPa) |
|---|---|---|---|
| 00:00 | 17° | 1018 | |
| 01:00 | 17° | 1018 | |
| 02:00 | 17° | 1018 | |
| 03:00 | 17° | 1018 | |
| 04:00 | 17° | 1018 | |
| 05:00 | 16° | 1019 | |
| 06:00 | 16° | 1019 | |
| 07:00 | 17° | 1019 | |
| 08:00 | 17° | 1020 | |
| 09:00 | 17° | 1020 | |
| 10:00 | 18° | 1020 | |
| 11:00 | 19° | 1021 | |
| 12:00 | 20° | 1020 | |
| 13:00 | 22° | 1020 | |
| 14:00 | 23° | 1020 | |
| 15:00 | 24° | 1019 | |
| 16:00 | 24° | 1019 | |
| 17:00 |  24° | 1019 | |
| 18:00 |  23° | 1019 | |
| 19:00 | 22° | 1019 | |
| 20:00 | 21° | 1019 | |
| 21:00 |  19° | 1019 | |
| 22:00 | 18° | 1019 | |
| 23:00 | 17° | 1019 |
Of the seven days, Monday moves most: down 5 hPa.
The highest reading, about 1021 hPa, comes this morning; it falls from there.
Seattle has a strong daily rhythm: pressure swings about 3 hPa between a regular low and high, at almost the same hours each day. Most of what the graph shows is that daily wave, which is why the change since yesterday says more here than the change over a few hours.
Seattle sits 72 m above sea level, so a barometer in the city reads about 9 hPa lower than the sea-level figure. A home station set to the local reading should show about 1011 hPa as of 08:00.
The hours already past are the model's record of each hour as it passed, anchored to real observations, though not a reading from an instrument in Seattle.
About Seattle
Seattle's barometer is busier than it looks. The monthly averages sit within about 4 hPa of each other all year, a very flat seasonal curve. The days are busier: roughly 48 sharp swings a year, spread through autumn, winter and spring, with summer almost exempt. Outside the warm months, the pressure rarely stays calm for more than four or five days. Even so, the pressure tops 1020 hPa on more than a hundred days a year. The overall picture is a high, level base that gets disturbed often, but briefly.
Sources: WikipediaERA5 reanalysisElevation: Copernicus DEM via Open-Meteo
Cities nearby
Open one to see its pressure, or search for your own city at the top of the page.
Wondering if this weather is normal? See what the weather in Seattle has done since 1940, on our sister site 
weatherjourney.com.
Common questions
What is a normal barometric pressure?
Near 1013 hPa at sea level; the exact standard figure, 1013.25 hPa, is the same as 760 mmHg, 29.92 inHg or 101.3 kPa. Anything between roughly 1000 and 1025 hPa is ordinary. Which way it is going matters far more than the number itself.
Why does my own barometer show a different number?
Usually altitude, and sometimes the instrument itself. Weather services correct readings to what they would be at sea level, so that cities can be compared. The figure for Seattle, which stands 72 m above sea level, is in the note above: about 9 hPa below the sea-level reading. If your barometer is already set to sea level and still reads slightly differently, that is the setting on the instrument rather than the weather.
Is a millibar the same as a hectopascal?
Yes. One millibar and one hectopascal are exactly the same amount of pressure, so 1013 mbar and 1013 hPa mean the same thing. The name changed; the number did not.
Does falling pressure mean rain?
Not by itself. Away from the tropics, falling pressure usually means a low is approaching, and lows carry the fronts that bring cloud and rain, so the two often arrive together. But a shallow fall can pass with nothing more than cloud, and rain falls under steady pressure too. The graph tells you a system is on the way, not how wet it will be. The week ahead, just above, shows the rain forecast beside the pressure.
