9 rules for a saner, drier world. 

Stop me if this one sounds familiar: You’re caught outside in a squall, clinging to one of those flimsy burner umbrellas. Up along the way, you spot a clearing that appears to be walking toward you. Like Moses parting the waters, this figure parts the sidewalk, ushering aside poor souls who don’t carry "chosen" umbrellas.

It's the dread urban golf umbrella user.

Or maybe that’s you: dry under your own personal awning, relishing the satisfaction that comes in planning ahead. Why should even a single inch of you be sogged when you had the foresight to check your weather app first thing, dig out that convention-swag umbrella, and carry it like a weather-repelling wizard's staff? Haters can get drenched.

Rain is trouble enough without the micro-frictions that arise between pedestrians during bad weather. We owe it to ourselves and each other to do things properly. To wield, at long last, our umbrellas like civilized adults.  

Rule #1: Do you plan to build a resort at your destination?

No? Then leave the golf umbrella at home. Even President Barack Obama doesn't carry a golf umbrella (or rather ask the Marines to do it for him). And even if he did, you are not the President, and it is not a national priority that you stay dry at the expense of others' comfort—namely the people with whom you share the sidewalk.

Rule #2: Find out how rainy your city really is.

The National Oceanic and Atmospheric Administration’s National Climatic Data Center measures precipitation in a number of ways, but two datasets drill right down to rainy-day metrics: normal annual precipitation (measured in mean inches) and the number of days with precipitation of 0.01 inch or more (mean number of days).

San Juan, the only major quasi-U.S. city located in a tropical monsoon climate zone, is by any measure the rainiest big city in America. The capital of Puerto Rico sees rain 194 days out of the year, and gets an average of 56.35 inches per year. Miami is another terrifically rainy city, receiving an average 61.90 inches per year, over an average 126 rainy days annually. If you live in Miami or San Juan, you get a golf umbrella dispensation. In fact, skip right to the beach umbrella.

Most rainy  cities, though, don't get both a lot of rain and a lot of rainy days. Seattle enjoys (suffers?) 50 percent more days with precipitation than Atlanta, but Atlanta gets about a third more precipitation on average. (NOAA’s precipitation data, sorted here by the top 50 U.S. cities by population, include snowfall, but most cities that record a lot of snowfall aren't very large, because snow is terrible.)

Average Annual Precipitation in 15 Major U.S. Cities
City Mean Volume (Inches) City Mean Days of Precipitation
Miami 61.90 San Juan 194
San Juan 56.35 Cleveland 150
Memphis 53.68 Seattle 150
Houston 52.69 Portland 148
Jacksonville 52.39 Columbus 133
New York 49.94 Detroit 128
Atlanta 49.71 Miami 126
Nashville 47.25 Boston 120
Louisville 45.54 Indianapolis 120
Boston 43.77 Milwaukee 119
Tulsa 43.73 Louisville 119
Raleigh 43.34 Chicago 119
Baltimore 41.88 Philadelphia 113
Charlotte 41.63 Nashville 113
Philadelphia 41.53 New York 113

OK, so most people don’t consult a weather table to find out whether it's rainy where they live. But national weather patterns are shifting. In 2013, cities across the South got soaked. Asheville, North Carolina, and Macon, Georgia, both experienced their wettest years in decades. Chattanooga and Atlanta saw their 4th wettest years in 74 and 84 years, respectively. Knoxville saw the most rain it’s seen in 104 years. Northern Midwest states also set precipitation records for snow.

Meanwhile, Sacramento, San Francisco, and Fresno, California, all suffered their driest years in more than 65 years. In Oregon, Portland’s 26.75 inches of rain for 2013 falls short of its average for 1981–2010 by more than 9 inches. Bone-dry cities across California and Oregon set records last year.

Rule #3: Size up your sidewalks.

One thing that’s constant across the nation’s weird weather regions is the standard for sidewalk design—or rather, the consistent lack thereof. Most state and local guidelines "recommend" building sidewalks that are at least 1.525 meters (60 inches) wide, according to the Federal Highway Administration’s Office of Planning, Environment, and Realty. While that might sound roomy enough for two people carrying umbrellas to pass by one another peaceably, it’s really not. Also, actual sidewalk widths vary to the point that there are just no broad guarantees. 

Pedestrians also avoid walking in the area of sidewalks known to planners as the “shy distance”: on one side, the part of the sidewalk hugged by buildings and used by people entering and exiting storefronts, and on the other, the part occupied by utility poles, tree boxes, bus-stops, and other obstacles. The shy distance can vary from city to city and from block to block. But the more shy distance you get taking up the design width of a sidewalk, the likelier an umbrella is to knock pedestrians off the path.

This effective sidewalk width—design width minus shy distance—could theoretically be expanded, or at least regularized, across the nation in the foreseeable future. That’s because the U.S. Access Board aims to expand guidelines set by the Americans With Disabilities Act to include regulations for public rights of way. The new guidelines would recommend a minimum four-feet width within all new or updated sidewalks in order to meet accessibility requirements.

But those guidelines are still a ways off. (And note that the guidelines won't tell states and local governments how big to make new sidewalks. Instead, they define the minimum effective width of accessible path that sidewalks need to contain in order to meet ADA compliance.)

Rule #4: Pick an umbrella that respects your fellow pedestrians.

All this is to say that the sidewalks you have are the sidewalks you’re going to need to work with for the foreseeable future. Personal umbrellas, on the other hand, come in all—including, unfortunately, ginormous.

“Umbrella sizes are measured in arc diameter,” says Dave Kahng, CEO of Davek New York, a company that makes umbrellas that The New York Times describes as “the perfect extreme accessory.” Kahng insists that no one in the business thinks of umbrellas in terms of width, but he gives me these measurements anyway: A golf umbrella with a 62-inch arc diameter has a width of 54 inches—well greater than an effective sidewalk width of 48 inches.

A range of umbrella styles by Davek New York

“You’re not going to be able to beat coverage on a long-shafted umbrella,” Kahng says. He recommends non-collapsing “long-shafted” umbrellas for consumers living in the suburbs, where a sidewalk's effective width may be broader than its urban counterpart's. Or for cities that get a lot more rain than pedestrian traffic: Mobile, Alabama, for example, whose 65.28 inches of rain per year on average beats out that of even Miami.

Davek New York’s most popular umbrella, the collapsible Solo (arc diameter 42 inches, straight diameter 37 inches), outsells the company’s long-shafted models by 4 to 1. Kahng says that customers who choose the convenience (and courteousness) of a collapsible umbrella aren’t necessarily trading on quality—the Solo, he boasts, is made with carbon steel, aircraft-grade aluminum, fiberglass, and 190–thread count fabric.

Special courtesy rules apply to collapsible umbrellas. Never place a wet umbrella on a bus seat, for instance, and hold your umbrella out for the person behind you as you exit a building (who can do the same for the person behind her). Also, never use an umbrella whose canopy has detached from its ribs in some way, which is every cheap umbrella in a storm, ever. “When you do that, it’s actually pretty dangerous to pedestrian traffic,” Kahng says.

Rule #5: Should you wear a rain poncho?

You should not wear a rain poncho.  You are bound to run into other people when you're entering and exiting buildings or boarding buses and trains, processes that slow way down when there's weather. Wearing a rain poncho may make you maximally dry, but it also makes you maximally irritating to the people who run into you. Hoods restrict visibility, which could lead to more accidents, although rain ponchos usually come in bright colors that are sure to catch a driver's eye. Most importantly, though,  you are a self-respecting adult who doesn't leave the house dressed in a garbage bag. Other kinds of ponchos are fine.

Rule #6: Embrace the umbrella, since you're stuck with it.

The design of the umbrella hasn't changed terribly much over the millennia. Collapsible umbrellas may have been in use in 6th century B.C. China; umbrellas are quite a bit older. Are we making any progress on this front?

“That’s a pretty tried-and-true technology,” says Nicolas Lee, a professor of aeronautics and astronautics at the California Institute of Technology. Lee studies deployable membrane structures, in particular collapsible membranes that can be unfolded in space to support applications such as radars for satellites and even solar sails. While he says he doesn’t work on membranes with “terrestrial weather” in mind, some of the same lessons apply on Earth as in space.

“If you deploy an umbrella, and you hold it out in the wind, the surface will deform. Worst case, it flips inside out,” Lee says. “We can’t have that if we’re using the geometry of the antenna to control our radar performance or solar-sail thrust.”

In space, only one solar-sail application has been successfully tested so far: Japan’s Interplanetary Kite-craft Accelerated by the Radiation Of the Sun (IKAROS). Unlike a solar sail mounted on a boom that expands (like an umbrella), IKAROS was deployed by spinning—a more complex dynamic in which the membrane is supported by centrifugal forces. “In terms of the structure, if you’re operationally able to accommodate the spinning, it’s a simpler structure to have, and it gives a more benign level of stress to the structure itself,” Lee says.

The Japan Aerospace Exploration Agency celebrates the third birthday of IKAROS,  a spacecraft that may not influence umbrella design at all.  Via @Ikaroskun.

For a traditional umbrella design, every point of articulation—the hinges along the ribs, the springs in the collapsing mechanism—is potentially a point of failure. (As pretty much everyone knows who's bought a $10 one-use umbrella from a drugstore.) A membrane that spins features far fewer potential points of failure. While Lee thinks spinning membranes are the right way to think about deploying solar sails (and other large applications) in space, he doubts this approach will work during a storm.

“If everyone’s holding these things that are rapidly spinning over their heads—I don’t think there’s any point to developing a spinning-deployment application,” he says.

Rule #7: Practice your umbrella dance.

If we’re stuck with traditional umbrellas, narrow urban sidewalks, and increasingly unpredictable weather, we as city residents need to coordinate. Kahng says that everyone should learn from Tokyo's "umbrella dance."

Here are the basic steps: Carry your umbrella, which should be no greater than 50 arc-diameter inches in length (43 straight-diameter inches), at a 45 degree angle, behind or in front of your head, depending on the wind. Never hold an umbrella straight up: Someone walking behind you could get poked in the eye as you stop short to avoid the splash of a passing car. 

When you need to pass someone carrying an umbrella—and you’re going to if you’re carrying a cane umbrella with an effective width of 43 inches on a sidewalk with an effective width of 48 inches—defer to the right. This is key. It's tempting to thrust an umbrella up or pull it down when passing another umbrella, so as to maintain uninterrupted rain coverage. But do this wrong, and you wind up colliding.  

Not so when you defer to the right with your umbrella. That way, you’re moving the umbrella toward the so-called shy distance of the sidewalk—the part closer to the splash lanes of passing vehicles, or the drip perimeter of building awnings. You also ensure that your drop water falls on you (that's the streaming water that will fall off the raised left side of your umbrella as you're tiling it to the right). That's right: falls on you. It's rain. You're going to get wet.

Rule #8: Don't try to outrun the rain.

How best to stay dry during the rain is hotly debated by physicists. One thing's for sure: You can't outrun it.

Picture the Flash in a downpour. The Flash can run so fast that the rain falling overhead will never land on him. He's the Flash. But because he's moving so fast, he is running smack into all the rain that is falling right in front of him. In a storm, the Flash would be perfectly dry on his head, back, and shoulders, missing every drop from above. But his front would be soaked, since he ran right into every drop before it could hit the ground. 

Stepping out from under the rain means stepping out into the rain. So trying to outrun the rain may mean that your feet and legs only get wetter. It will definitely mean that you will run into other pedestrians more often. Instead, invest in rain boots to keep your feet dry, and keep pace with pedestrian traffic. 

Rule #9: Remember that you are not made of sugar. 

As unpleasant as the rain can be, in most cases it will not kill you. Don't make a storm worse by being rude about it. If you’re living in a city that gets more rain by volume, or if you’re just that hip, invest in the long-shafted (but not golf!) umbrella. If you’re living in a city that sees more rainy days than rain per se, get a collapsible umbrella. Either way, hold it to your right when you pass someone in a storm. At least until we get our personalized overhead spinning disc things.

Top image: Budimir Jevtic /

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