Heat is the deadliest climate threat to humanity; More people die from heat each year than from floods, hurricanes, and wildfires combined.

And the risk is greatest in cities, which are warming twice as fast as the rest of the planet because of the urban heat island effect.

As dangerous temperatures become more common, city leaders around the world, from Paris to Phoenix, are strategically planning to expand shade coverage.

But it’s the sweltering island nation of Singapore that may well already have the best shade infrastructure of any city on the planet.

Its residents have long had their own tricks for dealing with torrential rain and sticky heat.

And chief among them may be covered sidewalks.

The source of this public shade is unclear. Although these “five-foot passageways” that crisscross the ground floors of arcaded shops and houses resemble the porticoes of Bologna, they may have originated in Southeast Asia. Stamford Raffles, the British colonial official credited with founding Singapore in the early 19th century, included them in his first town plan in 1822. Raffles demanded clear, continuous, covered passageways on both sides of every street to ensure efficient traffic in adverse weather conditions. Eventually, his “verandahed ways” (open, roofed verandas) fell into disuse. But Lee Kuan Yew, the powerful prime minister who guided Singapore to independence in the 1960s, revived them in a modern form. Lee was a micromanager and had a particular interest in climate and comfort. He believed that humidity was holding back the country's economic productivity.

Indoors, he transformed Singapore into what journalist Cherian George called the “air-conditioned nation.”

Outdoors,He was a fan of shade.

Covered Walkways

Lee was known for lecturing his subordinates about the poor design of paths and promenades, sometimes kneeling on the scorching ground to demonstrate.

In the 1960s and 1970s, as Lee's authoritarian government built towering public housing complexes, architects kept the ground floors of all buildings open to the air, preserving these areas as “community courtyards” where residents could gather to enjoy the breeze.

In the late 1980s and 1990s, Singapore's housing and transport agencies mandated the construction of freestanding metal canopies over sidewalks to ensure dry paths to the nearest bus or train.

Today, authorities claim to have erected around 200 kilometers of covered walkways.

Try Imagine if New York's ubiquitous construction scaffolding were permanent sidewalk architecture, and you'll get a sense of what this unattractive yet functional achievement looks like.

In the United States, developers must set their buildings back from the street to let in more light, but in Singapore they must contribute to the shading network by creating 8 to 12 feet of pedestrian overhangs on the ground floors of their buildings. Research suggests that bus shelters have a similar effect to a clean, well-designed bus stop.

Just as a bus stop can speed up the wait for a bus, Singaporeans also report that a walk under the walkways feels 14 percent shorter than one in the sun.

“We’re in a tropical region where it’s always extremely hot and humid,” says Yun Hye Hwang, a landscape architect and professor at the National University of Singapore.

With daily highs hovering around 31–33°C year-round, “you always need shade,” she adds.

As for shade, almost everyone would prefer a lush roof formed by tree branches and leaves to a clunky aluminum one, but greenery isn’t always the solution, says Lea Ruefenacht, a former researcher with Cooling Singapore, a government initiative on urban heat.

However, she notes that trees do generate cooling through shade and the release of water into the air: in humid Singapore, higher humidity can aggravate the situation.

Green and gray shades

For comfort, Ruefenacht recommends a balance between green and gray tones.

In Singapore, the densest gray shade is found flush with the concrete of the downtown skyscraper forest.

Developers must provide what authorities consider sufficient shade on outdoor plazas, cooling at least 50% of seating areas between 9:00 a.m. and 4:00 p.m.

Shade can come from a variety of sources (trees, umbrellas, awnings), but in their circular designs, the authorities demonstrate that it can also provide the penetrating shadow of a nearby tower.

This approach contrasts with New York City, where building shading in outdoor spaces is discouraged, and the mere threat of its existence can thwart new development.

In that colder climate, developers are told to locate their plazas on south-facing, sunlight-filled sidewalks to generate winter warmth (in fact, plazas are not allowed to face north).

Singapore has a different priority.

Ideally, developers place plazas on the east sidewalk of their buildings, so they can be cooled by afternoon shade. It's an unusual place where urban shade is encouraged as a public benefit.

“In tropical regions of the world, part of the problem has always been that settlements inherit building codes from temperate regions, and they don't necessarily have the means to review them and ask, 'Is this in our best interest?'” questions Kelvin Ang, director of conservation at Singapore's Urban Redevelopment Authority.

“In Singapore, there was somehow a huge awareness that building codes and planning codes should encourage shade, because of the intensity of the sun,” he adds.

Planners believe that if a public space doesn't have shade, no one will use it.

“Give me shade first”

Despite the potential effects on humidity, Prime Minister Lee demanded trees everywhere, convinced that a “clean and green” Singapore would be attractive to foreign investors.

Under his watch, a newly formed parks and trees unit beautified major boulevards, covering them with the spreading canopies of angsanas, rain trees, mahogany, and acacia.

“Flowers are fine,” Lee told the department head, “but give me some shade first.”

In the 1970s, when implementing congestion pricing and other schemes to wean Singaporeans off cars and onto public transit, Lee turned his attention to sidewalks, crosswalks, and bus stops, where a blazing sun might have scared off potential new users.

In Los Angeles, for example, trees are the final piece of the street-design puzzle,dropped through concrete holes and laid haphazardly on sidewalks after every vault and meter has been dug, every curb built, every gutter cut, and every driveway poured.

In Singapore, however, Lee ordered his land-use planners to consider them from the start.

The overhead power lines that disfigure Los Angeles sidewalks and reduce tree density are rare. Most utilities are installed underground in vaults that run alongside street trees and their roots.

Green infrastructure is planned by city planners, designed by public works agencies, and managed by a parks board whose budget increased tenfold under Lee's leadership.

Funding and coordination have proven to be the difference between a thriving urban forest and a bunch of sad urban trees.

In addition to roads, Lee's city planners imposed green space on private developments, regenerating a new garden city to compensate for the natural rainforest that had all but disappeared.

Social Equalization Factor

The Singapore government had a lot of power. Thanks to strict eminent domain rules, he owned roughly 90 percent of the land, and building inspectors wouldn't authorize occupancy until they saw trees on the ground.

Singapore's sprawling public housing estates also featured lawns, leafy courtyards, and tree-lined walkways that connected to parks and nature reserves.

As a result, trees are abundant in Singapore, in both wealthy and poor neighborhoods.

“We made no distinction between middle-class and working-class areas,” Lee wrote in his memoirs, noting that it would have been “politically disastrous” for the People's Action Party.

This sets Singapore apart from American cities, where shade is a reliable indicator of economic inequality.