Chance

Your favorite weather app just rolled out a minute-by-minute weather forecast! It says that at 3:14pm there will be isolated thunderstorms with a 20% chance of rain. When a forecast notes isolated thunderstorms, it means that at any given time, 10-20% of the area will be covered by thunderstorms. A chance of rain is defined as the probability that a single point in the area receives rain, averaged over all points in the area. The sound of thunder can travel up to ten miles.

If you are standing in the middle of Houston, where it is not raining, what is the chance that you can hear thunder?