Barometric pressure in Santa Rosa
Air pressure rose slowly over the last 24 hours. A rise of 1 hPa since this time yesterday. The rise is coming to an end: from here it falls until Wednesday afternoon.
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.
Climbs in the morning, then settles back.
14° / 2°low 1024 · high 1028 hPa
Falls quickly, most of it in the afternoon.
16° / 5°low 1017 · high 1025 hPa
Falls quickly, most of it in the afternoon.
17° / 9°low 1008 · high 1017 hPa
Dips in the afternoon, and comes back by the end of the day.
16° / 11°2.4 mmlow 1003 · high 1008 hPa
The same daily dip.
22° / 9°low 1005 · high 1008 hPa
Edges up slowly through the day.
20° / 7°low 1008 · high 1010 hPa
Climbs in the morning, then settles back.
18° / 9°0.6 mmlow 1010 · high 1013 hPa
Hour by hour
| Hour | Weather and temperature | Rain (mm) | Pressure (hPa) |
|---|---|---|---|
| 00:00 |  6° | 1025 | |
| 01:00 | 6° | 1025 | |
| 02:00 | 5° | 1026 | |
| 03:00 | 5° | 1026 | |
| 04:00 | 4° | 1026 | |
| 05:00 | 3° | 1026 | |
| 06:00 | 3° | 1026 | |
| 07:00 | 2° | 1027 | |
| 08:00 |  3° | 1027 | |
| 09:00 | 4° | 1028 | |
| 10:00 | 6° | 1028 | |
| 11:00 | 8° | 1028 | |
| 12:00 | 11° | 1028 | |
| 13:00 | 12° | 1027 | |
| 14:00 | 13° | 1026 | |
| 15:00 | 14° | 1025 | |
| 16:00 | 14° | 1024 | |
| 17:00 | 13° | 1024 | |
| 18:00 | 13° | 1024 | |
| 19:00 | 11° | 1024 | |
| 20:00 | 10° | 1025 | |
| 21:00 | 8° | 1025 | |
| 22:00 | 7° | 1025 | |
| 23:00 | 6° | 1025 |
Of the seven days, Tuesday moves most: down 9 hPa.
The lowest reading, about 1003 hPa, comes on Wednesday afternoon; it climbs from there.
Santa Rosa sits 178 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 1004 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 Santa Rosa.
Cities nearby
Open one to see its pressure, or search for your own city at the top of the page.
Watching the sun as well? See how strong the UV is in Santa Rosa right now, 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 Santa Rosa, which stands 178 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.
