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Is it really worth running in the rain? (1987) [pdf] (uniud.it)
67 points by anacleto on Feb 4, 2016 | hide | past | web | favorite | 39 comments

"Science for more than a half-century has found ways to complicate the matter ..."

Peterson, T. C. and Wallis, T. W. R. (1997), Running in the rain. Weather, 52: 93–96. doi: 10.1002/j.1477-8696.1997.tb06281.x


  But all this is model and theory. What about reality? To predict the weather four 
  days in advance you may want to use a model, but to truly determine whether a walker 
  or a runner would get wetter in the rain one can simply conduct an experiment. ... 
  we purchased two identical pairs of hats, sweat shirts and pants, ... Departing 
  at the same time, Dr Wallis ran the lOOm at a velocity of 4.0ms-' while Dr Peterson 
  walked the same distance at 1.4ms-'. The total water absorbed by the walker was 
  0.217kg and by the runner 0.130 kg. 
  Running, therefore, produced a decrease in wetting of 40 per cent.

This calls for follow-up research on how the absorption ratio varies with distance traveled. Please excuse me while I apply for some grant money.

Argumentum de evolution:

I find it intriguing but also somewhat self-satisfying that the natural response (to run), placed in our DNA by evolution, is confirmed by both mathematics and experiment. One wonders why one should have asked at all!8-))

Actually, if you run fast enough, you can get wetter because of water projections by you legs/feet. You can end up with a wet back, wet lower legs, and nearly dry front.

As delazeur said lower, this calls for follow-up research!

Mythbusters actually tested this (http://mythresults.com/episode38), and LifeHacker showed a little video on it (http://lifehacker.com/5970476/why-you-should-run-not-walk-in...).

The real issue, for me, has always been shoes. Most clothing dries fairly well, but shoes and socks are a tough matter. Besides, if it's unpleasant to be in, you should run, and if it's pleasant to be in, take your time.

Also in episode 1:

- http://mythresults.com/episode1

Priorities are clear (;

"There is something to be learned from a rainstorm. When meeting with a sudden shower, you try not to get wet and run quickly along the road. But doing such things as passing under the eaves of houses, you still get wet. When you are resolved from the beginning, you will not be perplexed, though you still get the same soaking. This understanding extends to everything."



from the Hagakure

The main benefit of running is the fact that you reach your destination faster and have more time to dry. Specifically the thighs (if wearing say jeans) certainly benefit from the extra time. As pointed out by other posters the biggest risk at faster speeds is splashing and I'd add the risk of slipping as well.

The experiment also seems to assume that it'll rain a constant amount. That's reasonable but if it can be expected that the rain will increase (maybe it just started), running becomes even better. Conversely if you somehow know it is more likely to decrease, walking becomes better (as you might even hit a window where it doesn't rain at all that you'd simply miss by running).

I certainly enjoyed this sentence though:

""" ‘optimal’ solutions, cases in which the experimenter assumes strange angles with respect to the ground, are not considered, being awkward to obtain in reality. """

Personally, I find the question of "waiting it out" way more intriguing. Murphy seems to let the rain continue endlessly whenever I decide to seek shelter temporarily.

> The main benefit of running is the fact that you reach your destination faster and have more time to dry

Bonus marks for considering ecological validity

I love this work but the entire underlying premise is shaky! It assumes that a person's discomfort is proportional to the quantity of wetness they experience rather than the total amount of time spent in wet conditions.

In the abstract the author writes:

Is it worth running as fast as possible to get less wet?

So the author is only trying to answer the question of whether you will get less wet if you run in the rain. He is not making any claims about comfort. The author's only premise is:

The purpose of this paper is to put an end to this kind of useless argument.

[edit:] clarity

I also think the distribution of water is an important unmeasure factor. It can be less uncomfotable to be a little wet all over than to be soaked in a smaller area.

I would concur with the article's recommendation of a brisk walk, because when running in the rain you risk slipping and falling, which puts you contact with the wet ground, and prolongs the time you spend out in the rain.

OTOH, in lightning conditions it may be advantageous to move as fast as possible as a strike may result in significantly prolonged contact with wet ground.

Concerning thunderstorms, it is usually best to keep an eye on the conditions and get a decent headstart to outrun them, I think.

Sounds like it needs a large scale Monte Carlo trial to assess the impact of this effect. "Further study is needed."

Somewhat off-topic but entertaining questions on Rain answered by Randall Monroe:

- "What if a rainstorm dropped all of its water in a single giant drop?" [1]

- "At what speed would you have to drive for rain to shatter your windshield?" [2]

[1] https://what-if.xkcd.com/12/

[2] https://what-if.xkcd.com/93/

The title should clarify that this focuses on whether running vs walking results in getting fewer raindrops on you:

It concludes:

"As suggested by common sense, when it is raining it is better to move fast. By running faster you get less wet. but the benefit that you get beyond the speed of a brisk walk does not justify the supplementary effort. "

Personally, I love running in a light rain just for comfort reasons and (presumably) the negative ions.

Jogging in the rain: that's what I thought the article was about before I clicked. I love to jog in the rain, as long as it's not too cold and not raining too hard. It's lovely.

Same. I also expected to see an interesting discussion in these comments about improvements in running shoe and clothing technology that make it more pleasant. The article describes sweatpants, for goodness sake! I can hardly imagine anything less comfortable to run in!

I think the best clothing technology for running in the rain has already been invented, and, in fact pre-dates both clothing and technology. :)

This is obviously true - you pass through the same amount of water horizontally on the way to your destination, but there's less time for it to fall on you vertically. However, the main problem with running in the rain if you're not careful is that you will spray yourself with water from your shoes. That may or may not get you wetter, but it could also get your clothes dirty. I aim for a short of shuffle-jog. :P

I made an interactive calculator of this a while ago, adapted from a BBC article. You can see it here (interactive equation at the bottom):


Note that it doesn't do oblique angles.

EDIT: I've been meaning to update this with a graph for a while -- the plot in the article really illustrates the tradeoff between wetness and velocity quite well.

The article, at best, seems inconclusive...

I thru-hiked the Appalachian Trail years ago...admittedly, I was walking, with a pack, not running...

If I was within sight of shelter (a rarity) I sometimes trotted, and stayed a bit dryer...usually I just walked on, smiled, and tried to find things to enjoy...

One thing I learned was that it didn't matter one whit if I got wet when hypothermia was not a factor...the only important thing was whether or not, once I'd enjoyed the rain, I had dry clothes in my pack to change into while I cooked my supper...

I think we undervalue the good feeling rain falling on us offers...kids instinctively experience it as something special and dance around in it...imagine that...

We could re-learn things from them...rain's nothing to fear...

If the rain comes, they run and hide their heads

I feel sorry for them...

Were the kids you appear to be referencing in your comment taught to fear rain for some reason...by adults?

My experience has been the opposite...

(just curious)

As a child, you get wet and when you are done, someone changes you: an adult. There is no downside. As an adult, you get wet and you know someone has to change you: you. If you don't change into dry, warm clothes, then you know you will get sick. In light of that, you learn that it might just be more convenient to stay dry. That trumps and drowns out the temporary joy.

Sure, sometimes it's more convenient to work at staying dry...especially if you need to be dry for a reason--work, an appointment, grocery shopping, etc...I'm pointing out and advocating something different...

Getting wet or cold; neither "causes" sickness...that theory was debunked years ago...

I commute to work in cities for some of my gigs, but don't live in them...my leisure time is mine...getting wet..?...It's just not that big of a deal when I have no pressing business...fear of getting wet is no reason to miss the magic of standing out in the rain...

We lead different lives, my friend...and both are OK...

>> We lead different lives, my friend...and both are OK...

Absolutely and thank goodness for that variety. I was just putting up an explanation for why kids like playing in the rain and why adults typically do not.

Debunked? I'd be interested in seeing a source for that. I keep having to debate this with my mum and my girlfriend to no avail; they can't seem to let go of the wisdom of the ancients they believe their parents passed on to them.


Nothing bullet-proof definitive here, but the consensus certainly seems to be that colds are caused by virus entering the respiratory system, nothing more.

Good work at finding a way to work in how you thru-hiked the Appalachian Trial into a posting about rain!

You deserve a pat-on-the-back for the careful and tedious thought required to join such disparate topics, much like the constant struggle against the elements you had to face, step by step, and the invaluable rewards you must have received on your epic journey!

Brave, smart, enlightened... not to get off topic, but what other interesting qualities do you have, and the stories and wisdom to go with them, oh great "Outdoorsman"?

Edit: o why the downvote o great master? What thou request of thine?

You're getting downvoted because you're being snarky and condescending for no obvious reason. Outdoorsman's post was on-topic and I have no idea why you've taken offense to it.

He was obviously bragging about what he did. Normally I wouldn't mind. But trying to segue from a topic on how to avoid getting wet when going a short distance through rain to how he trekked the entire Appalachian Trail is just fucking ridiculous!

Please don't post uncivil or unsubstantive comments to Hacker News. This one was both, which is no doubt the reason for the downvotes.

Also, the HN guidelines ask you not to go on about getting downvoted. See the two rules at the bottom:


When running, your body is oblique, reducing the surface area of the impinging rain. There are so many more factors than what this theoretical paper considers, but it is a good start. I don't feel the Mythbusters experiment was valid, since they used simulated rain, only did the experiment once, and tested only a very small distance. I also feel that making a good TV show gets in the way of the goal of making a good experiment.

How has this paper not won an IgNoble prize?

I use to run it order to quicker get some shelter. I did not know it had positive side effects.

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