Barometric pressure in Yuen Long
Taking each day as a whole, pressure has barely moved. A fall is beginning, and runs until this afternoon.
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 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.
Dips in the afternoon, and comes back by the end of the day.
31° / 28°3.6 mmlow 999 · high 1002 hPa
Edges up slowly through the day.
30° / 27°14.4 mmlow 1001 · high 1004 hPa
Edges up slowly through the day.
30° / 26°21.6 mmlow 1001 · high 1005 hPa
Eases down slowly through the day.
32° / 27°2.7 mmlow 1000 · high 1004 hPa
Dips in the afternoon, and comes back by the end of the day.
31° / 28°4.5 mmlow 999 · high 1002 hPa
Barely moves all day.
30° / 25°41.1 mmlow 1000 · high 1002 hPa
Rises steadily through the day.
31° / 26°12.9 mmlow 1001 · high 1004 hPa
Hour by hour
| Hour | Weather and temperature | Rain (mm) | Pressure (hPa) |
|---|---|---|---|
| 00:00 |  29° | 1002 | |
| 01:00 | 29° | 1001 | |
| 02:00 | 29° | 1001 | |
| 03:00 | 28° | 0.1 | 1000 |
| 04:00 | 28° | 0.1 | 1000 |
| 05:00 | 28° | 0.1 | 1000 |
| 06:00 | 28° | 0.5 | 1001 |
| 07:00 | 28° | 0.5 | 1001 |
| 08:00 | 28° | 0.5 | 1002 |
| 09:00 | 29° | 0.1 | 1002 |
| 10:00 | 30° | 0.1 | 1002 |
| 11:00 | 31° | 0.1 | 1002 |
| 12:00 | 31° | 0.2 | 1001 |
| 13:00 | 31° | 0.2 | 1000 |
| 14:00 | 31° | 0.2 | 1000 |
| 15:00 | 31° | 0.2 | 999 |
| 16:00 | 30° | 0.2 | 999 |
| 17:00 | 30° | 0.2 | 999 |
| 18:00 | 30° | 1000 | |
| 19:00 | 30° | 1001 | |
| 20:00 | 29° | 1002 | |
| 21:00 | 29° | 0.1 | 1002 |
| 22:00 | 29° | 0.1 | 1002 |
| 23:00 | 29° | 0.1 | 1002 |
Sunday has the week's biggest move: up 3 hPa.
Pressure bottoms out near 999 hPa this afternoon, and rises after that.
In Yuen Long pressure moves on a daily clock: about 3 hPa between its regular low and high, at much the same hours every day. That daily swing is most of the shape you see on the graph, so the change since yesterday tells you more here than the change over the past few hours.
Yuen Long 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 Yuen Long.
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 Yuen Long, 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. Weather services correct readings to what they would be at sea level, so that cities can be compared. Yuen Long 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.
