Originally Posted By: KG2V
Originally Posted By: comms
...snip...
it is effing hot this week. +111 degrees all week and the dew point is over 55* which is a indicator of monsoon season. Don't ask me more on dew point, its not humidity, but its somehow relevant.

The SAR unit here is top notch. They have never NOT found their target, even after searching for many weeks.


Dewpoint and Humidity is 100% related - the "dewpoint" is the point where if you lowered the temperature of the air, dew would form - aka 100% humidity

If you know the temperature and the dewpoint, and want to obtain relative humidity, the formulas are as follows:

Convert BOTH temps to degs C - inn your case

111F = 44C (Tc - air temp)
55F = 13C (Tdc - dewpoint temp in C)

The next set of formulas assumes a standard atmospheric pressure. These formulas will calculate saturation vapor pressure(Es) and actual vapor pressure(E) in millibars.

(5) Es=6.11*10.0**(7.5*Tc/(237.7+Tc))

(6) E=6.11*10.0**(7.5*Tdc/(237.7+Tdc))

Once you have the saturation vapor pressure and the actual vapor pressure, relative humidity can be computed by dividing the actual vapor pressure by the saturation vapor pressure and then multiplying by 100 to convert the quantity to a percent.

(7) Relative Humidity(RH) in percent =(E/Es)*100



I use my own method to calculate relative humidity.

1. Take one test vessel(frosty mug) from the freezer
2. pour in 12 oz of the chilled test fluid, preferably Leinenkugels Honey Weiss
3. observe the frosty coating on the test vessel while slowly extracting the test fluid orally

If it melts before the third sip, the humidity is 85%
If it melts before the second sip, the humidity is 95%

Warning: this calculation can be compromised by the 'thirstyness factor'

If the test fluid is gulped, the test results are invalid and steps 1 through 3 must be repeated.
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The man got the powr but the byrd got the wyng