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> 30% chance of rain actually means 30% of the area is projected to have rain covering it

Common misconception. The Chance of precipitation is actually stating that historically, given these conditions x% of days produced precipitation. It is a statement of the odds that it will rain at all.

http://www.straightdope.com/columns/read/854/what-does-it-me...



That site you provide (or cite) is the only one I can find that describes it that way. Every other source describes the otherway which I still think is correct:

NOAA: http://www.srh.noaa.gov/ffc/?n=pop

http://www.usatoday.com/weather/resources/askjack/wadefine.h...

http://en.wikipedia.org/wiki/Probability_of_precipitation


Even those links state the PoP is a measure of the chance that it will happen at all. That is the historical measurement.


No, that is the simplified explanation of how the average person should think about it. We are talking about the definition and a possible way to get the odd results the OP mentioned observing.




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