# Explained: Do you really get less wet walking in the rain than running?

• 22/07/2020

It's the bold claim that everyone's heard at least once: you'll get less wet walking in the rain than you would if you were to run.

Far from being an urban myth passed around on school playgrounds and around water coolers though, it's an issue that's been keenly debated by mathematicians and scientists for decades.

To most of us, it would seem counterintuitive to walk. After all, wouldn't running take us to shelter faster, reducing the amount of time spent in the rain?

This is a key component of the problem, but not the only one.

The other is that horizontal movement will cause you to come into contact with a greater number of rain droplets from the side, which suggests walking or even standing still might be better.

Harvard University mathematician David Bell was the first to try his hand at solving the mystery back in 1976.

Writing in The Mathematical Gazette, Bell posited that if the rain is falling vertically or there is a wind blowing from the direction you're headed, you should run.

However if the wind is blowing from behind you, Bell says running as fast as you can isn't always the best approach. Instead the optimal speed to travel at is the same pace as the wind.

That wasn't the end of the debate, though, with numerous experts having tried their hand at answering it since.

Discovery Channel's Mythbusters infamously showed walking would keep you drier in 2003, before revisiting the topic years later and proving the opposite.

Physicist Franco Bocci published a paper on the topic in the European Journal of Physics in 2012, arguing that the problem had long been oversimplified.

He said there were a myriad of factors at play that hadn't been considered properly in the past, including the person's height-to-breadth ratio, wind direction and raindrop size.

"The answer depends on the shape and orientation of the moving body and on wind direction and intensity," the study's abstract reads. "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.

However Prof Bocci admits it's likely that running as fast as you can is the best approach for most people.

"Let's say that in general, the best thing is to run, as fast as you can - not always, but in general," he told BBC News in 2012. "If you're really thin, it's more probable that there will be an optimal speed. Otherwise, it's better to run fast.72

The most perceptive findings, however, came from Italian physicist Alessandro De Angelis back in 1987.

He found that whichever strategy you opted for, running or walking, it didn't really matter - you'll still get wet if you're out in the rain.