The problem of choosing an optimal strategy for moving in the rain has attracted considerable attention among physicists and other scientists. Taking a novel approach, this paper shows, by studying simple shaped bodies, that the answer depends on the shape and orientation of the moving body and on wind direction and intensity. For different body shapes, the best strategy may be different: in some cases, it is best to run as fast as possible, while in some others there is an optimal speed.
Basically, the best strategy for staying dry (or at least somewhat dry) is to run as fast as possible. Unless you're really thin, in which case there may be a more optimal speed. And if you've got a tailwind behind you, then you should run exactly as fast as the wind at your back.
The battleground for this bit of hobby mathematics now seems to be the UK's Institute of Physics publication the European Journal of Physics. In 1987, another Italian researcher asserted in the journal
that changing strategies did not make a substantial difference. In 2011, a textile expert and a physicist used the same publication to suggest
that an optimal speed existed, depending on the wind direction....
What complicates the question is the human shape; for simplicity, previous attempts to crack the thorny problem assumed people to be thin sheets or upright, rectangular boxes.
When Prof Bocci considered a more general case--likely to be the case you would face in the rain--he found that the answer may depend on an individual's height-to-breadth ratio as well as wind direction and raindrop size.