It is one of the worst feelings - you have to cross an area of open ground, with no shelter whatsoever, and it is pouring with rain. You have no option but to brave the elements and you know that you will get soaking wet.
So you run across as fast as you can, but is that the correct approach?
There is a theory that no matter how quickly or slowly to make the journey you will hit the same number of raindrops!
The theory is that you will hit raindrops in a Parallelogram that has two parallel sides with a length equal to your height. And the distance between these two parallel sides is the length of your journey. The area of a Parallelogram is the length of a side multiplied by its distance from the side opposite (Base x Height).
So no matter how quickly you travel you will move through Parallelograms with the same area, and thus hit exactly the same number of raindrops - no matter how quickly you go, you get equally wet.
Now, it does not seem that way, so is it true?
It is not true because it takes into account only the rain that hits your front. The amount of rain that hits your head and shoulders is proportional to the time you spent in the rain.
Traveling on a windless day or into a headwind, go as fast as you can. But don't lean forwards as this increases your "top area". If the wind is from behind try to travel at the same speed as the wind.