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[pct-l] Dew Point

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Go here  http://www.doc.mmu.ac.uk/aric/eae/Weather/Older/Dew_Point.html

All air contains water vapour of varying quantities. The dew point indicate=
the amount of moisture in the air. The higher the dew point, the higher the
moisture content of the air at a given <A HREF=3D"http://www.doc.mmu.ac.uk/=
aric/eae/Weather/Older/Temperature.html">temperature</A>. Conversely, the d=
ew point
of humid air will be higher than the dew point of dry air.

Dew point temperature is defined as the temperature to which the air would
have to <A HREF=3D"http://www.doc.mmu.ac.uk/aric/eae/Weather/Older/Cooling_=
Air.html">cool</A> (at constant <A HREF=3D"http://www.doc.mmu.ac.uk/aric/ea=
e/Weather/Older/Pressure.html">pressure</A> and constant water vapour conte=
nt) in
order to reach saturation. A state of saturation exists when the air is
holding the maximum amount of water vapour possible at the existing
temperature and pressure.

<A HREF=3D"http://www.doc.mmu.ac.uk/aric/eae/Weather/Older/Condensation.htm=
l">Condensation</A> of water vapour begins when the <A HREF=3D"http://www.d=
oc.mmu.ac.uk/aric/eae/Weather/Older/Temperature.html">temperature</A> of ai=
r is lowered to
its dew point and beyond. The dew point, like other measures of <A HREF=3D"=
, can
be calculated from readings taken by a hygrometer.

We all should carry a hygrometer wrap in our tarp