meteorological office or by calculation: absolute air pressure ±0.11hPa per meter of the measuring location above/below mean sea level).
Wind chill equivalent temperature (perceived temperature)- A fictitious temperature, which the human body feels under certain conditions instead of the measured temperature, and which can be used at low temperatures (e.g. less than 45°F or 7°C) to say how comfortable one feels at certain temperatures and wind speeds whilst wearing appropriate clothing.
These conditions are a temperature below 92°F (33ºC) and a wind speed higher than 5.8 mph (2.6 m/s). Wind chill is defined as the cooling effect of uncovered skin at an assumed constant 92°F (33ºC) skin surface temperature.
The higher the wind speed is and the lower the actual temperature, the more noticeable is the wind chill effect.
The “perceived temperature” is roughly comparable to the
Wind strength table (Beaufort) |
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Beaufort | Wind speed | Description |
0 | calm | |
1 | slight breeze | |
2 | light breeze | |
3 | weak breeze | |
4 | moderate breeze | |
5 | fresh breeze | |
6 | strong wind | |
7 | stiff wind | |
8 | stormy wind | |
9 | storm | |
10 | heavy storm | |
11 | near hurricane storm | |
12 | > 73 mph (117.4 km/h) | hurricane |
Units |
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ºF | =[ ºC ] * 9 /5 +32 | |
ºC | =([º F ]– 32 )*5 /9 | |
mmHg | =[hPa ] *0.75006 | |
inHg | =[hPa ] *0.02953 | |
m/s | =[km/h ] //3.6 | =[km/h ] *0.27778 |
knots | =[km/h ] //1.852 =[km/h ] *0,53996 | |
mph | =[km/h ] //1.609 =[km/h ] *0.6215 | |
in | =[mm ] //25.4 =[mm ] *0.03937 | |
ft | =[m ] //0.3048 | =[m ] *3.28084 |
cu.in. | =[ml ] //16.387 =[ml ] *0.061024.94 | |
The Comfort Indicator (☺ ) represents the climatic conditions, for which the following table is used (the symbol status shows the area of validity):
Temperature Humidity |
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20% | 30% | 35% | 40% | 45% | 50% | 55% | 60% | 65% | 70% |
< 64.4°F (18ºC) |
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| ☺ | ☺ | ☺ | ☺ |
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| ☺ | ☺ | ☺ | ☺ |
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| ☺ | ☺ | ☺ | ☺ |
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over 82.4°F(28ºC) |
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It can be seen from this that, depending on the ratio of temperature to humidity, there are clearly bounded areas, which are defined as a comfortable or an uncomfortable climate. Hence, one finds a humidity level of 30% at a temperature of 77°F (25ºC), for example, to be too dry (e.g. heating air) and one above 60% to be oppressive.
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