# Running or riding a bike in the rain **URL:** \ **Category:** Factual Questions\ **Created:** [November 26, 2024, 1:43pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799 "2024-11-26T13:43:21Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![sbright33](https://avatars.discourse-cdn.com/v4/letter/s/8e8cbc/32.png) [@sbright33](https://boards.straightdope.com/u/sbright33)\ **Post date:** [November 26, 2024, 1:43pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/1 "2024-11-26T13:43:21Z")
Let’s say you’re a really tall thin person with a tiny head and shoulders. Almost like a piece of cardboard that runs facing forward. The area from above is Ah. The area from in front is Av. You know the rate of rainfall in Gal /ft2. Certainly running full speed would not be the ideal speed to stay dry. Is it easy to calculate the optimal speed? Can you guess what it is? Walking slowly, running, or riding a vertical step bike? How about 100mph Bionic Man? I only ask because I’m going out in a storm and I don’t know what speed to walk… I’m 6’5 and I recently lost a bunch of weight… ---
**Author:** ![andrewm](https://avatars.discourse-cdn.com/v4/letter/a/c57346/32.png) [@andrewm](https://boards.straightdope.com/u/andrewm)\ **Post date:** [November 26, 2024, 1:48pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/2 "2024-11-26T13:48:26Z")
Faster is better: [A Physicist Reveals Why You Should Run in The Rain : ScienceAlert](https://www.sciencealert.com/a-physicist-reveals-why-you-should-run-in-the-rain) ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [November 26, 2024, 1:52pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/3 "2024-11-26T13:52:57Z")
[The Master Speaks.](https://www.straightdope.com/21342001/which-will-keep-you-drier-running-through-the-rain-or-walking) And [here’s a calculator](http://www.dctech.com/physics/notes/0006.php). Not sure how good the model is. ---
**Author:** ![sbright33](https://avatars.discourse-cdn.com/v4/letter/s/8e8cbc/32.png) [@sbright33](https://boards.straightdope.com/u/sbright33)\ **Post date:** [November 26, 2024, 2:01pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/4 "2024-11-26T14:01:35Z")
Great answers! Aerodynamic effects matter even more when you’re shaped like a piece of thick cardboard. And I have a waterproof hat. So 100mph wins for a normal person. A piece of cardboard stays completely dry walking slowly, with a hat. Assuming a 1mph breeze from the rear! ---
**Author:** ![sbright33](https://avatars.discourse-cdn.com/v4/letter/s/8e8cbc/32.png) [@sbright33](https://boards.straightdope.com/u/sbright33)\ **Post date:** [November 26, 2024, 2:06pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/5 "2024-11-26T14:06:28Z")
If you were similar to a thick piece of cardboard or 3D box… Say 10x wider than your thickness. You could walk sideways at a slower speed, then running facing forward so… An average human can remain completely dry. Assuming a 1mph breeze from the rear and a hat! ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [November 26, 2024, 2:52pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/6 "2024-11-26T14:52:03Z")
Speaking from experience, what you want is a waterproof/windproof outfit, think Gore-Tex or similar. Then you will stay dry, no matter how fast or slow you go. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [November 26, 2024, 3:54pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/7 "2024-11-26T15:54:56Z")
Lol, I thought this was going to be about slip hazards. I wore some fuzzy socks last weekend and damned near ate shit on a bit of slick flooring in my own house and now falling down is in my mind. ---
**Author:** ![xtenkfarpl](https://avatars.discourse-cdn.com/v4/letter/x/c2a13f/32.png) [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)\ **Post date:** [November 26, 2024, 4:04pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/8 "2024-11-26T16:04:30Z")
Dammit, I want a forcefield to keep the rain off. Preferably generated by a convenient gizmo you can clip to your belt. A Spindizzy would do the job… useful for other things too. See James Blish’s Cities in Flight SF series…🙂 ---
**Author:** ![commasense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/commasense/32/3017_2.png) [@commasense](https://boards.straightdope.com/u/commasense)\ **Post date:** [November 26, 2024, 4:14pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/9 "2024-11-26T16:14:41Z")
The Mythbusters concluded that walking in the rain kept you drier in this video: [![](https://img.youtube.com/vi/a2axIxq0QM4/hqdefault.jpg "Walking vs. Running in the Rain") ](https://www.youtube.com/watch?v=a2axIxq0QM4) But apparently they revisited their methodology later and found that they were wrong, and running is better. Unfortunately, I wasn’t able to find a video of the second test in the time I felt like spending looking for it. ---
**Author:** ![Spiderman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spiderman/32/230_2.png) [@Spiderman](https://boards.straightdope.com/u/Spiderman)\ **Post date:** [November 26, 2024, 5:31pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/10 "2024-11-26T17:31:45Z")
I’ve run / ridden in the rain lots. When running my back stays dry, just like your car windshield gets more rain than your rear window but the opposite is true when ([road](https://images.giant-bicycles.com/xum4rnsmri9byrk75pz4/preview.jpg)) cycling. My back / shoulders get soaked but the front of my jersey stays (somewhat) dry because it’s on the bottom, out of direct contact with the rain. I’d also wear socks, newspaper delivery bags (remember those) & shoes, in that order, on my feet. I can ride in just about anything but squishy socks are just the makings of misery! > [@DPRK](#): > > Speaking from experience, what you want is a waterproof/windproof outfit, think Gore-Tex or similar. Then you will stay dry, no matter how fast or slow you go. I’ve never found Gore-Tex to be as good as advertised when running in that it the sweat doesn’t escape as much as marketing leads you to believe it will & that you end up steamy on the inside; especially if it’s not real cold out. ---
**Author:** ![wguy123](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wguy123/32/3161_2.png) [@wguy123](https://boards.straightdope.com/u/wguy123)\ **Post date:** [November 26, 2024, 5:50pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/11 "2024-11-26T17:50:13Z")
> [@commasense](#): > > But apparently they revisited their methodology later and found that they were wrong, and running is better. Unfortunately, I wasn’t able to find a video of the second test in the time I felt like spending looking for it. I think round two they did the testing on a treadmill. ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [November 26, 2024, 6:13pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/12 "2024-11-26T18:13:49Z")
> [@Spiderman](#): > > I’ve run / ridden in the rain lots. When running my back stays dry, just like your car windshield gets more rain than your rear window but the opposite is true when ([road](https://images.giant-bicycles.com/xum4rnsmri9byrk75pz4/preview.jpg)) cycling. Well, yes. A mud guard might help with water spraying right up your ass, but I have never bothered installing one myself. > [@Spiderman](#): > > I can ride in just about anything but squishy socks are just the makings of misery! In the tropics, one solution is to ride in sandals 🙂 ---
**Author:** ![Spiderman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spiderman/32/230_2.png) [@Spiderman](https://boards.straightdope.com/u/Spiderman)\ **Post date:** [November 26, 2024, 6:57pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/13 "2024-11-26T18:57:22Z")
> [@DPRK](#): > > Well, yes. A mud guard might help with water spraying right up your ass, but I have never bothered installing one myself. I was more saying because the falling rain is hitting my back since one rides a road bike hunched over, but you’re right about the mudguard. I have a quick mount/dismount one that I would put on for when I went out in the rain., it was not regularly on the bike ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 26, 2024, 9:18pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/14 "2024-11-26T21:18:45Z")
Walking in the rain is equivalent to running in the rain, but then stopping at the end and waiting out in the rain for the time it takes the walker to catch up, before going indoors. Which should make it clear that running is better. When we bring in biking, though, there’s another very relevant factor, that I know from a lot of experience of biking in the rain: When you’re biking, your thighs spend approximately half of the time approximately horizontal, as opposed to staying very close to vertical while walking. This results in your legs getting much wetter than if you were on foot. ---
**Author:** ![Princhester](https://avatars.discourse-cdn.com/v4/letter/p/3e96dc/32.png) [@Princhester](https://boards.straightdope.com/u/Princhester)\ **Post date:** [November 27, 2024, 2:59am UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/15 "2024-11-27T02:59:58Z")
Thereby telling me something I could probably have guessed - you don’t live in the subtropics. Where I’m from, except in midwinter even light exercise in the rain gives you two options - get wet from rain or get wet from sweat. The former is more pleasant. Gore-tex’s claimed breathability doesn’t do jack to prevent the latter. ---
**Author:** ![md-2000](https://avatars.discourse-cdn.com/v4/letter/m/9d8465/32.png) [@md-2000](https://boards.straightdope.com/u/md-2000)\ **Post date:** [November 27, 2024, 3:07am UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/16 "2024-11-27T03:07:16Z")
IIRC Ann Landers or Dear Abby had endless reader letters about this. Here’s my take. I leave this as an exercise for the reader… 😃 Instead of worring about how fast, etc. consider it from th viewpoint of raindrops. They are all standing still (absent persistent gusts) So you have a random scattering of drops which we can assume have a constant density just standing still in midair. Just imagine the rain is standing still and you are moving upward through it at the same speed as it is actually falling. (The weatherman’s version of Relativity). A person standing still is basically a top-down silhouette that describes a column upward through this scatter, sweeping up all rain they encounter at a speed (and hence distance) determined by how long they stand there and how fast the rain really is falling. I.e. if rain is falling at 5ft/sec and you stand there for 1 minute, you do the equivalent of sweep a column 300 feet by the area of your max crossection of raindrops, of the density of the rainfall. .A person walking, running or riding essentially sweeps a swath through this scatter at a diagonal direction - upward and forward, but the same logic applies. Calculate the volume of the column for the distance, time, and cross-section you present to the rain and that describes a volume of raindrops you hit. ---
**Author:** ![sbright33](https://avatars.discourse-cdn.com/v4/letter/s/8e8cbc/32.png) [@sbright33](https://boards.straightdope.com/u/sbright33)\ **Post date:** [November 27, 2024, 12:57pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/17 "2024-11-27T12:57:33Z")
The key is to run sideways! This takes practice. Or run downwind. At precisely the correct speed of the wind. Walk back when it’s sunny out. We get to choose which direction we run right? Don’t forget your “Build Back Better” hat! ---
**Author:** ![sbright33](https://avatars.discourse-cdn.com/v4/letter/s/8e8cbc/32.png) [@sbright33](https://boards.straightdope.com/u/sbright33)\ **Post date:** [November 27, 2024, 12:59pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/18 "2024-11-27T12:59:02Z")
Excellent point Princhester! Lived in Costa Rica. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [November 27, 2024, 1:12pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/19 "2024-11-27T13:12:12Z")
> [@commasense](#): > > But apparently they revisited their methodology later and found that they were wrong, and running is better. Unfortunately, I wasn’t able to find a video of the second test in the time I felt like spending looking for it. Adam, just about a week and a half ago, covered this very topic on his channel. When they tested it on the show, they found that you’d stay dryer by walking, but by an insignificant amount and you have to keep in mind that this test was done under extremely controlled circumstances. When they (Kari/Tori/Grant) ran the test a second time, they got the opposite result, but they did it in real world conditions that weren’t repeatable. Here’s the clip, the relevant part is ~2:00-4:00 [![](https://img.youtube.com/vi/0qTsHXJo7LU/maxresdefault.jpg "You're WRONG About This MythBusters Result") ](https://www.youtube.com/watch?v=0qTsHXJo7LU&t=115) ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [November 27, 2024, 5:55pm UTC](https://boards.straightdope.com/t/running-or-riding-a-bike-in-the-rain/1010799/20 "2024-11-27T17:55:17Z")
If you do not get sweaty, you are not doing it right 🙂 But I can tell you one trick: unzip the front of your jacket. As discussed, since you are hunched forward, most of the rain falls on your back anyway.