Barometric pressure in Shiyan today
Falling
Apart from the daily swing, pressure has eased down over the past day. It now reads 2 hPa lower than at this time yesterday. From here it moves between 1009 and 1012 hPa until tomorrow afternoon, then rises sharply until Sunday morning. After that it moves between 1018 and 1023 hPa until Tuesday afternoon, then rises sharply until Wednesday morning, then falls quickly until Thursday afternoon.
Current sea-level reading for Shiyan, as of 19:00 local time.
Pressure graph: the past week and the week ahead
The shaded part shows the days already gone. The thicker line is the forecast.
Shiyan sits 242 m above sea level, so a barometer in the city reads about 28 hPa lower than the sea-level figure. A home station set to the local reading should show about 984 hPa as of 19:00.
The week ahead: the pressure forecast day by day
Each day at a glance: which way pressure moves, and how far.
22° / 17°1.2 mmHolds near 1015 until morning, then falls quickly to 1012 by the afternoon, and holds there.Show hourly graph
23° / 18°24.3 mmSwings between 1009 and 1018 hPa and ends much higher.Show hourly graph19° / 15°5.4 mmMoves between 1018 and 1023 hPa as the overall level rises quickly, ending clearly higher.Show hourly graph
20° / 14°1.5 mmMoves between 1018 and 1022 hPa as the overall level eases down, ending clearly lower.Show hourly graph26° / 14°Moves between 1018 and 1027 hPa as the overall level rises quickly, ending much higher.Show hourly graph15° / 13°Swings between 1026 and 1031 hPa and ends a little lower.Show hourly graph16° / 10°0.6 mmHolds near 1025 until morning, then falls quickly to 1020 by the afternoon, then edges back up a little.Show hourly graphBiggest change of the week: Tuesday, up 8 hPa.
Hour by hour
| Hour | Weather and temperature | Rain (mm) | Pressure (hPa) |
|---|---|---|---|
| 00:00 |  17° | 1015 | |
| 01:00 | 17° | 1015 | |
| 02:00 |  17° | 1015 | |
| 03:00 | 17° | 1015 | |
| 04:00 |  17° | 1015 | |
| 05:00 | 17° | 1015 | |
| 06:00 | 17° | 1015 | |
| 07:00 | 17° | 1016 | |
| 08:00 | 18° | 1016 | |
| 09:00 | 19° | 1016 | |
| 10:00 | 20° | 1016 | |
| 11:00 | 21° | 1015 | |
| 12:00 | 21° | 1014 | |
| 13:00 | 22° | 1013 | |
| 14:00 | 22° | 1012 | |
| 15:00 | 22° | 0.2 | 1012 |
| 16:00 | 21° | 0.2 | 1012 |
| 17:00 | 21° | 0.2 | 1012 |
| 18:00 | 20° | 0.1 | 1012 |
| 19:00 | 20° | 0.1 | 1012 |
| 20:00 | 20° | 0.1 | 1012 |
| 21:00 | 20° | 0.1 | 1012 |
| 22:00 | 20° | 0.1 | 1012 |
| 23:00 | 20° | 0.1 | 1012 |
How much the pressure changes in Shiyan
In Shiyan the pressure changes most in March. In a typical October it changes by about 1.8 hPa from one day to the next, and it hardly ever rises or falls by more than 10 hPa.
When the pressure changes most
| Month | More than 5 hPa | More than 10 hPa |
|---|---|---|
| January | 6 | 1 |
| February | 7 | 1 |
| March | 9 | 1 |
| April | 7 | 1 |
| May | 5 | 0 |
| June | 1 | 0 |
| July | 0 | 0 |
| August | 1 | 0 |
| September | 1 | 0 |
| October | 3 | 0 |
| November | 6 | 1 |
| December | 7 | 1 |
A typical day’s change through the year
Each date of the year has its own bar. The taller the bar, the bigger a typical day’s change around that date.
Does the pressure change a lot in Shiyan?
Shiyan has more days with a change of more than 10 hPa than 63 out of every 100 large cities.
Each dot stands for up to 20 cities with 100,000 people or more. The first column is much taller than shown. Cities higher than 1,000 m are left out, and so are smaller cities within 15 km of a bigger one, unless they are capitals, so that suburbs are not counted twice.
These figures come from ERA5, in which the European weather centre ECMWF rebuilds past weather from a weather model and observations, for an area about 28 km across around Shiyan, 1991 to 2020. Each change is the difference between one day’s average pressure and the next day’s.
Cities nearby
Open one to see its pressure, or search for your own city at the top of the page.
More about air pressure
What we have written about how pressure behaves and how it is measured.
Where air pressure changes the most, city by city
Thirty years of data, ranked by city: where air pressure swings most from day to day and where it hardly moves. London, New York, Tokyo and 128 more.
How much does air pressure change in a day?
A normal day moves the barometer about 4 hPa in London and half of one in Singapore. What counts as a big drop, and how often one comes.
Why barometric pressure deserved its own site
Air pressure is the weather number people ask about most and understand least: is it high, is it rising or falling, does it matter today.
Is this weather normal for the season? See how these days compare with Shiyan weather since 1940, on our sister site 
weatherjourney.com.
Questions about the pressure in Shiyan
What is the barometer reading in Shiyan right now?
Sea-level pressure in Shiyan is 1012 hPa as of 19:00 local time, unchanged over the last three hours. A barometer in the city itself, 242 m up, shows about 984 hPa.
Is the barometer rising or falling in Shiyan today?
Apart from the daily swing, pressure has eased down over the past day. It now reads 2 hPa lower than at this time yesterday. Over the last three hours it has not changed.
Has the pressure in Shiyan changed since yesterday?
Yes. At this time yesterday it read 1014 hPa; it is 2 hPa lower now.
What has the pressure in Shiyan been over the last few days?
Over the past 7 days it ran between 1012 hPa (this afternoon) and 1025 hPa (on Tuesday morning). The biggest change in any 24 hours was a rise of 6 hPa, in the 24 hours ending on Monday night.
Is 1012 hPa high or low pressure?
Atmospheric pressure between about 1000 and 1025 hPa is ordinary at sea level. 1012 hPa sits in the middle of that range. In Shiyan most days average between 1001 and 1032 hPa. The last 24 hours average about 1014 hPa, within that usual range.
What is normal barometric pressure for Shiyan?
From 1991 to 2020 the sea-level average for Shiyan was 1016 hPa, and most days average between 1001 and 1032 hPa. It is usually highest in December and January and lowest in July.
When does barometric pressure change the most in Shiyan?
The pressure in Shiyan changes most in March. Between 1991 and 2020, Shiyan had about 6 days a year with a big change, of more than 10 hPa from one day to the next.
Why does my own barometer show a different number?
Usually altitude, and sometimes the instrument itself. To compare cities, pressure is corrected to sea level. The figure for Shiyan, which stands 242 m above sea level, is in the note above: about 28 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.
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.
