Barometric pressure in San Justo
Air pressure has been rising slowly over the last 24 hours. It stands 3 hPa higher than it did at this time yesterday. There is more to come: it climbs until tomorrow morning.
Sea level reading, as of 14:00 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.
Rises steadily through the day.
12° / 3°low 1024 · high 1028 hPa
Falls steadily through the day.
11° / 3°low 1024 · high 1029 hPa
Falls quickly, most of it in the afternoon.
13° / 7°low 1016 · high 1024 hPa
Falls quickly, most of it in the afternoon.
19° / 9°0.5 mmlow 1006 · high 1016 hPa
Edges up slowly through the day.
19° / 12°10.0 mmlow 1005 · high 1009 hPa
Rises steadily through the day.
20° / 9°low 1008 · high 1012 hPa
Edges up slowly through the day.
18° / 7°low 1011 · high 1015 hPa
Hour by hour
| Hour | Weather and temperature | Rain (mm) | Pressure (hPa) |
|---|---|---|---|
| 00:00 |  7° | 1024 | |
| 01:00 | 6° | 1024 | |
| 02:00 | 5° | 1024 | |
| 03:00 | 4° | 1025 | |
| 04:00 | 4° | 1025 | |
| 05:00 |  3° | 1025 | |
| 06:00 | 3° | 1025 | |
| 07:00 | 3° | 1026 | |
| 08:00 | 4° | 1026 | |
| 09:00 | 5° | 1027 | |
| 10:00 | 7° | 1027 | |
| 11:00 | 9° | 1027 | |
| 12:00 | 11° | 1027 | |
| 13:00 | 12° | 1027 | |
| 14:00 | 12° | 1026 | |
| 15:00 | 12° | 1026 | |
| 16:00 | 12° | 1026 | |
| 17:00 | 11° | 1026 | |
| 18:00 | 10° | 1026 | |
| 19:00 | 9° | 1026 | |
| 20:00 | 8° | 1027 | |
| 21:00 | 7° | 1027 | |
| 22:00 | 6° | 1028 | |
| 23:00 | 6° | 1028 |
Biggest change: Wednesday, down 9 hPa.
The highest reading, about 1029 hPa, comes tomorrow morning; it falls from there.
San Justo sits 32 m above sea level, so a barometer in the city reads about 4 hPa lower than the sea-level figure. A home station set to the local reading should show about 1022 hPa as of 14:00.
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 San Justo.
Cities nearby
Open one to see its pressure, or search for your own city at the top of the page.
Out in the sun today? Check the UV level in San Justo, on our sister site 
uvi.today.
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 San Justo, which stands 32 m above sea level, is in the note above: about 4 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.
