StormSeek allows to calculate the distance from you and where the lightning falls, during the thunderstorm.
When it's raining and you don't know what to do, it can be a interesting and funny way to trick the time. See at the window and calculate the distance of the lightning direcly from your iPhone.
It's easy: press "FLASH" when you see the lightning in the sky and press "THUNDER" when you hear the thunder.
The distance is expressed in KM and in MILES and you can also see the chronology of the distances in order to see how the thunderstorm is moving in the sky.