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According to the Norwegian meterological institute, the answer is that it is best to run. According to Mythbusters (quoted in the comments to that article), the answer is that it is best to walk.

My guess would be that this is something that can be properly modelled mathematically and solved. I suspect that I'm not alone in making a start on this, but as it's usually during a rainstorm that I think of it, I don't get far before deciding that the best strategy is to call a taxi!

I would also guess that someone has already done this and figured out the answer. If I'm right about that, I would like to read about it and learn what the real answer is. Thus my question is most likely: can someone provide a reference for this?

(If I'm wrong that it's already been solved, then some pointers as to how to solve it or even an explanation of what the main issues are, would be most interesting.)

As well as simply satisfying my curiosity, this is also one of those questions that non-mathematicians often ask (or at least, that non-mathematicians can easily understand the motivation for the question) so if there's a reasonable answer then it would be a good way to show off some mathematics.

Update This question has a long and curious history. There's a discussion about it at the meta site: http://mathoverflow.tqft.net/discussion/90/question-about-walking-in-the-rain

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Andrew Stacey
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    Andrew, I'm voting this down to register my preference: this kind of question is not what I want MO to be for. Of course that's just my personal taste. It would be different if you'd put up evidence that there was interesting mathematics to be found here. – Tom Leinster Nov 18 '09 at 12:50
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    -1. I agree with Tom. – S. Carnahan Nov 18 '09 at 15:51
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    @Tom (and Scott): That's precisely my question! Is there any interesting maths here? (But I have no quarrel with the down votes, I'm still trying to work out what makes a "good" question, since my research-level ones tend not to get answered!) – Andrew Stacey Nov 18 '09 at 16:15
  • Closed, I agree with the comments above, and there appears to be an excellent answer already. – Scott Morrison Nov 18 '09 at 17:00
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    @Scott: Is that a reason to close it? Surely I should just accept that answer and then let this one drift downwards. – Andrew Stacey Nov 18 '09 at 17:14
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    I find this strange. What's so bad about Andrew's question? A questiomn that has as an answer a full-fledged math article that at least 7 people so far indicate is useful can't be that bad.

    What is off-topic here? The fact that the question involves high-school math? Are questions involving high-school math off topic here? They can still be pretty hard to answer!

    I find there are plenty of questions on the forum that are not as suitable as this one. Puzzles me.

     – Urs Schreiber Nov 18 '09 at 18:20
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    And besides: this down-voting of people who one can just as well reasonably talk to is something I find rather irritating and unworthy of a forum for what should be grown-ups. – Urs Schreiber Nov 18 '09 at 18:21
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    I also do not see why this question was closed. I think this is a very interesting question, one that I ("a full-time mathematician") have wondered about many times myself. From the article referenced in the answer below, we see that, although it is perhaps clear that the question only requires basic calculus, the question is still a fairly non-trivial one. – Kevin H. Lin Nov 18 '09 at 19:11
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    I'm against the closing either. The question needed 12 pages of math to be "fully" solved, not to mention the five papers with mistaken or uncomplete answers and the two Mythbuster episodes. – Jose Brox Nov 19 '09 at 18:14
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    As this question's now being discussed at meta (http://tea.mathoverflow.net/discussion/81//why-do-you-hate-applied-math), I'll try to explain my view. What I disliked about the question was that Andrew didn't present any evidence that there was anything mathematically interesting going on. (Indeed, he used the words "particularly dull".) It's very easy to ask questions of the form "Here's a real-world situation. Is there any interesting math behind it?" You could rattle off dozens of such questions. Whether there turns out to be interesting math behind this question is beside the point. – Tom Leinster Dec 09 '09 at 01:59
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    I voted to reopen the question, see the thread on Meta http://tea.mathoverflow.net/discussion/90/question-about-walking-in-the-rain/ – Ilya Nikokoshev Dec 11 '09 at 17:04
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    I'd encourage anyone interested to participate in Ilya's project to re-write and reopen. I'd be happy to see this reopened. (Before you jump, Ilya has specifically asked that no one with moderator powers votes to reopen!) – Scott Morrison Dec 11 '09 at 20:26
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    It is a good question mathematicians often think about. – Zoran Skoda Apr 05 '10 at 13:18

1 Answers1

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try this, the latest in a long line of recreational mathematics on the topic

"Keeping Dry: The Mathematics of Running in the Rain" Dan Kalman and Bruce Torrence, Mathematics Magazine, Volume 82, Number 4 (2009) 266-277

Gerald Edgar
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    The article is available online here: http://stanwagon.com/public/TorrenceRainMathMag.pdf – Kevin H. Lin Nov 18 '09 at 19:03
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    Also, this very same question is the subject of the following article - http://sputnik.master-telecom.ru/Seans/Kvant/1989/03/kak_ubegat_ot_dozhdya.htm - in Kvant, which is a sort of Russian recreational mathematics magazine. I don't know if an english translation is available. – alex Mar 15 '10 at 02:49
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    That first link is now dead; the article is at http://www1.math.american.edu/People/kalman/pdffiles/rain.pdf. – joriki Aug 07 '12 at 14:21
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    The second link is now dead; the article is found at http://www1.american.edu/cas/mathstat/People/kalman/pdffiles/rain.pdf – knedlsepp May 05 '15 at 20:32
  • It seems I can still get upvotes on answers to closed questions. Today I received the Guru badge for it when it achieved the 40th upvote. – Gerald Edgar Feb 12 '21 at 12:22