going off on a tangent here, since you mentioned weather prediction, chance of rain % or probability of precipitation (pop) are computed not only for probabilit

going off on a tangent here, since you mentioned weather prediction, chance of rain % or probability of precipitation (pop) are computed not only for probability of rain in a given area but also for area of location that will receive the rain if any at all, ie 60% here expresses combination of degree of confidence that rain will occur in an area and geographic coverage of that rain. more details on the wiki entry here - https://en.wikipedia.org/wiki/Probability_of_precipitation https://en.wikipedia.org/wiki/Probability_of_precipitation