Barometric pressure in Charleston
Beneath its daily wave, pressure has fallen slowly. Down 1 hPa since this time yesterday. The fall is giving way to a rise that lasts until Sunday morning.
Sea level reading, as of 00:00 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 dotted 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.
Rises steadily through the day.
28° / 24°4.8 mmlow 1015 · high 1018 hPa
Edges up slowly through the day.
28° / 22°15.3 mmlow 1018 · high 1021 hPa
Eases down slowly through the day.
29° / 24°5.1 mmlow 1018 · high 1021 hPa
Dips in the evening, and comes back by the end of the day.
29° / 24°8.7 mmlow 1017 · high 1020 hPa
Barely moves all day.
30° / 24°2.1 mmlow 1017 · high 1019 hPa
Eases down slowly through the day.
30° / 25°4.2 mmlow 1016 · high 1019 hPa
Falls steadily through the day.
32° / 25°0.9 mmlow 1013 · high 1018 hPa
Hour by hour
| Hour | Weather and temperature | Rain (mm) | Pressure (hPa) |
|---|---|---|---|
| 00:00 |  25° | 1015 | |
| 01:00 | 25° | 1015 | |
| 02:00 |  25° | 1015 | |
| 03:00 | 25° | 1015 | |
| 04:00 | 24° | 1015 | |
| 05:00 | 24° | 1015 | |
| 06:00 | 24° | 1016 | |
| 07:00 | 24° | 1016 | |
| 08:00 | 24° | 1017 | |
| 09:00 | 25° | 1017 | |
| 10:00 | 27° | 1018 | |
| 11:00 | 28° | 1018 | |
| 12:00 | 28° | 0.3 | 1018 |
| 13:00 | 28° | 0.3 | 1018 |
| 14:00 | 28° | 0.3 | 1017 |
| 15:00 | 28° | 1.0 | 1017 |
| 16:00 | 28° | 1.0 | 1016 |
| 17:00 | 28° | 1.0 | 1016 |
| 18:00 | 27° | 0.2 | 1016 |
| 19:00 | 26° | 0.2 | 1016 |
| 20:00 | 26° | 0.2 | 1017 |
| 21:00 | 25° | 0.1 | 1017 |
| 22:00 | 25° | 0.1 | 1018 |
| 23:00 | 25° | 0.1 | 1018 |
Thursday has the week's biggest move: down 3 hPa.
The high point comes on Sunday morning, near 1021 hPa; after that it falls.
Charleston has a strong daily rhythm: pressure swings about 2 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.
Charleston is at sea level, so a barometer there reads about the same as the sea-level figure.
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 Charleston.
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 Charleston 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. Weather services correct readings to what they would be at sea level, so that cities can be compared. Charleston is at sea level, so there is almost nothing to correct and the two figures agree.
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.
