Barometric pressure in Chicago
Air pressure has been rising steadily over the last 24 hours. It stands 4 hPa higher than it did at this time yesterday. It continues to climb until Tuesday morning.
Sea level reading, as of 10:00 local time.
The past week and the days ahead
The shaded part shows the days already gone. The thicker line is the forecast.
The week ahead
Each day at a glance: how far pressure moves, and the low and high it reaches.
Barely moves all day.
24° / 16°low 1015 · high 1017 hPa
Rises steadily through the day.
25° / 14°low 1016 · high 1019 hPa
Eases down slowly through the day.
26° / 15°low 1016 · high 1021 hPa
Falls steadily through the day.
29° / 18°1.2 mmlow 1010 · high 1016 hPa
Edges up slowly through the day.
27° / 19°2.1 mmlow 1012 · high 1015 hPa
Edges up slowly through the day.
28° / 17°low 1015 · high 1018 hPa
Falls steadily through the day.
30° / 17°low 1013 · high 1019 hPa
Hour by hour
| Hour | Weather and temperature | Rain (mm) | Pressure (hPa) |
|---|---|---|---|
| 00:00 |  18° | 1015 | |
| 01:00 | 17° | 1015 | |
| 02:00 | 16° | 1015 | |
| 03:00 | 16° | 1016 | |
| 04:00 | 16° | 1016 | |
| 05:00 | 16° | 1016 | |
| 06:00 | 16° | 1017 | |
| 07:00 |  16° | 1017 | |
| 08:00 | 18° | 1017 | |
| 09:00 | 19° | 1017 | |
| 10:00 | 21° | 1017 | |
| 11:00 | 22° | 1017 | |
| 12:00 |  23° | 1017 | |
| 13:00 | 24° | 1016 | |
| 14:00 | 24° | 1016 | |
| 15:00 | 24° | 1016 | |
| 16:00 | 24° | 1015 | |
| 17:00 | 23° | 1015 | |
| 18:00 | 22° | 1015 | |
| 19:00 | 21° | 1015 | |
| 20:00 | 20° | 1015 | |
| 21:00 | 19° | 1016 | |
| 22:00 | 18° | 1016 | |
| 23:00 | 18° | 1016 |
Saturday has the week's biggest move: down 6 hPa.
The high point comes on Tuesday morning, near 1021 hPa; after that it falls.
Chicago sits 179 m above sea level, so a barometer in the city reads about 21 hPa lower than the sea-level figure. A home station set to the local reading should show about 996 hPa as of 10:00.
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 Chicago.
About Chicago
Chicago's barometer works hardest in winter. Sharp day-to-day swings come on about 66 days a year, most of them from December through March. June to August often passes with hardly one. The seasons themselves are much milder: the monthly averages span only about 6 hPa between the February high and the June low. One practical note: the city stands about 178 m above sea level, so an instrument on the wall shows roughly 21 hPa under the sea-level numbers used on this page.
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 Chicago 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 Chicago, which stands 179 m above sea level, is in the note above: about 21 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.
