some information about air pressure

mean value at mean sea level (msl):     1013,25 hPa or 760 mmHg

extreme values:
historic lowest known air pressure at mean sea level:  870 hPa 12.10.1979 NW pacific ocean, 873 hPa 23.9.1958  in position 17  N / 135 E  (tropic storm)
historic low values:                                                            886,5 hPa  (Philippines 1927 typhoon),  922,8 (Shetland islands 1879), 946,0 11.1.2005 buoy 64045 northwest UK
 
historic highest value at sea level:   1083,8 hPa 31.12.1968 (Agata-lake Sibiria 66N/93E)

In Europe the air pressure is usualy between 950 und 1050 hPa. Mean value is 1013,2 hPa.

Corresponding values: (values in each row correspond)

 Pascal

hPa

mbar

kPa

Bar

mmHg/Torr

cm H2O

mm H2O

psi

in. H2O

in. Hg

1

0,01

0,01

0,001

0,00001

0,00750062

0,010197

0,10197

0,689476

0,00401458

0,0002953

100

1

1

0,1

0,001

0,750062

1,0197

10,1973

68,9476

0,401458

0,02953

1000

10

10

1

0,01

7,50062

10,197

100,1973

689,476

4,01458

0,2953

100 000

1000

1000

100

1

750,062

1019,7

10197

68947,6

401,458

29,53

133,3224

1,333224

1,333224

0,1333224

0,01333224

1

13,59488

135,9488

919,2259

5,352336

0,3937

98,068

0,98068

0,98068

0,098068

0,00098068

0,073557

1

10

67,61559

0,393702

0,028959

9,8068

0,098068

0,098068

0,0098068

0,00009806

0,0073557

0,1

1

6,761559

0,03937

0,0028959

14,5038

0,0145038

0,0145038

0,00145038

0,0000145

0,0010878

0,014789

0,147894

1

0,005822

2,03602

249,092

2,49092

2,49092

0,249092

0,00249092

0,18683

2,53999

25,3999

171,7622

1

0,0735486

3386,39

33,8639

33,8639

3,38639

0,0338639

25,399

34,53158

345,3158

0,49113

13,59508

1

Pascal

kPa

hPa

Bar

mbar

mm Hg

cm H20

mm H20

psi

in. H20

in. Hg

101300

101,3

1013

1,013

1013

759,7

 1032,95

 10329,5

 14,688

 406,92

29,883

theor. pressure in different heigths above sea level, if pressure at msl is 1013 hPa: *

Heigth msl in m hPa mbar mm Hg / Torr
0 1013,0 1013,0 759,7
1 1013,0 1013,0 759,7
10 1011,9 1011,9 758,8
100 1000,5 1000,5 750,4
500 952 952 714
1000 894 894 670
1500 840 840 630
2000 789 789 592
2500 741 741 556
3000 696 696 522
5000 541 541 406

5500m: about 50% of msl pressure

* values may differ depending upon temperature for example.

QFE:       real air pressure
QNH:      air pressure reduced at 0 msl and in ICAO atmosphere (15 degrees, 2 degrees drop per 1000 m)
QFF:       air pressure reduced at 0 msl (mean sea level) depending upon temperature, metres above msl humidity...

meaning of changes in air pressure   diurnal rhythm of air pressure   home