No umbrella but you need to dash out in the rain? Let physics be your guide! It is easy to calculate how much rain will hit you, and it turns out that running is not always the best idea.

Simply input the direction of the wind, its speed, and your body shape. After a bit of number crunching, you'll find your optimum speed (or often simply "as-fast-as-you-can"). For those in need of more data when they make a decision, there are graphs detailing the relative wetness of your front/back, head, and sides. What's more important to you? Your hair or your pants?

With this app you'll be able to find out how fast to go, and how to stay just a bit drier than everyone else.