On a really hot day in Washington ... in the kind of Washington heat when the flesh inside your elbow hisses unstuck as you straighten your arm and people on the streets move through the glare as if they're blind ... the kind of heat when Washington's streets stretch out, the whole city seems to shrug, smog sits on the horizon like a rotten rind and everything seems lost, preoccupied, provisional, endless ... it's on that kind of day that Washington is Washington.

This is why true Washingtonians love the heat. Heat is a kind of local god, a guardian angel, a genius loci. We love our heat the way San Francisco loves its fog or New York loves its neurosis. The heat turns Washington into a real city, instead of a city for people who hate cities. On hot days Washington looks mythical, even evil. It looks as if it has been here forever. This is the way cities should look, as in Rome the Eternal City, or in that line about "a rose-red city, half as old as time." Something about the heat here, the feeling of it ... April in Paris, autumn in New York, 97 degrees in Washington ... and the sun hanging over Rosslyn is as close to a vision of eternity as we're apt to get. Paris is the City of Light, Washington is the City of Heat.

For what it's worth, which isn't much, the data do not support us in our belief that Washington is a very hot city. The data insist that there are lots of other American cities that are hotter, like Phoenix, with average daily highs in July of 105. However, Phoenix is in a desert; that's dry heat. Then there's Miami, at 88.7, with average humidity of 85 percent at 7 in the morning and an average July wind speed of 7.8 miles an hour. In July we have a daily high of 87.9, humidity of 76 percent and wind at 8.2 miles an hour, according to Axel Grauman, a meteorologist at the National Climatic Data Center. Don't even think about playing in the international heat league, with cities like Cairo and Manila. "If you compare Washington with cities around the world, it isn't going to be near the top," Grauman says.

What do the data know? The data can tell us about only hot air, not hot people, or hot Washington.

Or a hot night at Carter Barron Amphitheatre, the spotlights hissing through the humidity, smoky tubes of light, and beyond them the little smears of fireflies -- it all seems heroic and exhausted, as if the city were under siege and you could hear the artillery in the distance, which you can, sometimes, when the thunderstorms gather over Virginia and Maryland. (And when the thunderstorms hit, we race around closing windows, feeling so exultant. Hail the size of chickpeas! Golf balls! Canned hams!)

Or the flat morning heat at 12th and G SE, where children sit next to a heap of bags and suitcases, waiting for the haze to generate a bus, the way the ancients believed that mud generated frogs. The bus is to take them to Camp Happyland, a Salvation Army camp near the Rappahannock River. But it's likely to be the city's heat, not the country's camp, that shows in their faces -- the slow, beaten faces of middle-aged people. Even children heading for camp look like that in the heat.

Or the mother at the country club in Maryland, venturing out of the shade to address the small figure who appears to have taken up permanent residence on the end of the high board.

"Jonathan," she says, "either jump or come down from there, now, please."

"I am," Jonathan says.

Time passes. The pool twinkles through thick air. In the distance, there is the small music of tennis balls.

"You are what," says the mother.

Jonathan thinks about this for a while. He has the sort of small-boy body that always looks like it's about to shiver.

"I am," he says, and refuses to explain.

Like the sun over Rosslyn, like the police helicopter that hovers at midnight making that horrible baritone clapping noise, he could be up there forever. There are no resolutions in heat like this, only inevitabilities.

Day after day.

In the early morning the cicadas grind up and up, like sirens. On the river by the Potomac Boat Club a one-man scull flickers over the gray water, precise and insubstantial, a figment of the last cool air of the day. At the Takoma Park subway station a young man waiting for a Ride-On bus gathers his lips and offers a bouquet of cigarette smoke to the humidity. There is a vegetable smell to things.

By noon the heat has won its usual smashing, vulgar victory, and it will spend the rest of the day leering through the windows of restaurants, pounding on cars stuck in traffic and threatening Perfect Georgetown Women with the democracy of sweat. This is another reason we like it -- it's a whiff of populism to ease our guilt at living so high off the taxpayers' hog. Amid the squalor of governance, it also gives us a common enemy, something we can agree on. Hot enough for you? Yes, indeed.

Everything glares, light without coherence, the optical equivalent of noise -- the greasy wink of windshields, the dusty trees.

The heat brings odd reversals: people walking through the glare as if they were feeling their way through a moonless night; sound bending through the dankness so when you walk, you don't hear your own footsteps but the footsteps of someone across the street; the feeling of unreality induced by the heat's very real assault. Our electrolytes go out of balance, our spit curdles, our hearts pound and the most immaculate Big Guy from a Connecticut Avenue law firm looks rumpled, right down to the horn-rimmed glasses and the boxer shorts. Washington becomes Baudelaire's "swarming city, city full of dreams/ where the spectre in broad daylight accosts the passerby." God, it's hot.

The glare drives our pupils into such tiny circles that the top of the noon sky looks black. The whole way we see things seems to reverse. Is this an illusion or are there physical reasons for it? A hypothesis: Ordinarily, looking at distance, we see a blurred foreground and a clear background. A hot day's glare narrows our pupils, increasing our depth of field, the way that closing the aperture of a camera increases its depth of field. We see the foreground more clearly. But the humidity blurs the background. Oddly clear foreground, oddly blurred background. It seems wrong, it makes us feel crazy.

Maybe this is why Washington looks evil on hot days. Washington looks evil only on hot days. Not that Washington lacks evil, but most of the time it has a republican purity that is almost poignant -- all that marble amid the hardwood forests of the East Coast, the avenues that dwindle off for miles into bungalow front yards and disused farmland, the melancholy earnestness of a colonial capital. Like New Delhi or the old Hong Kong, Washington looks as though it's trying to be its own suburb. If we wanted to build a monument to Washington, it would be a 500-foot-tall white marble barbecue cooker, down on the Mall. Grass and trees, pass the iced tea, please.

Then it gets hot. The edges come off things, distinctions ease, nothing is real and everything is possible. Tremble, oh ye puritans. No wonder that woman shot her husband in Gaithersburg, we say. No wonder the cops have all those guys braced against the liquor store wall, and nobody's paying the slightest attention. It's the heat, it's just so hot. "All that is solid melts into air," Marx says. "All that is holy is profaned." I remember one afternoon in the riotous summer of 1968, watching a kid smash a store window on 14th Street and pull out a pair of shoes. He did it slowly -- it was too hot to rush even looting, and the people standing at the bus stop in front of the window didn't bother to turn around. The heat takes away our constraints. It takes away appetites, too. The fan's on high and it's still too hot for love, or favorite arguments, or whatever.

"You want dinner?"

"I guess."

By the time it's dark, Washingtonians all seem to be leaning against something, breathing out. Or they're hiding inside bunkers of air conditioning, peering out at the globes of humidity that gather around the streetlights, at a dog tugging at a garbage can, its owner having decided to let it walk itself, in all this heat. There's a smattering of conga drums from Dupont Circle. Over on Florida Avenue three little girls practice a time step, slide/clap, slide/clap. It gets cooler now, but it gets danker. The sky turns a dirty pink.

The smell of a hot night in Washington: like a combination of Chinese restaurants and mothballs ... the sweet dead air that rises from parking garages, the stale scald from the wrong end of air conditioners, a burst of bus exhaust, mildew, the dry-ice cold that leaks from an ice cream truck, the river, attics so hot that the resin squeezes out of the beams in brown little drops, the chalky smell of sidewalks when the first raindrops hit.

Sounds: a great hiss of air conditioners, crickets, your thighs pulling at the car seat, ice melting in your drink, the dirty fidget of electric bug killers, tires ripping away from hot asphalt like bandages, and then a string of firecrackers unzips the dark and people laugh ...

Down at the Washington Monument the flags lift from their poles every once in a while, like old people who can't sleep and sit up in the darkness only to collapse back on their pillows again. In Falls Church a woman goes out for a slow walk through air-conditioning's deserted streets, past the empty porches of the suburbs. In the living rooms there is the light of televisions, sort of a shuddering.

Inside one of those houses a husband says to his wife, "You coming to bed?"

And she says, "I thought I'd stay up and watch the weather."

Heat. Washington.