Every winter sun list is the same list. Somewhere with a beach, ranked by average January temperature, with a paragraph about resorts. The only variable is the number, and the number is available on any weather site for free.

Here is a better question. Rather than asking where it happens to be warm in January, ask where January is the only time to go — where the northern winter opens something that is closed, invisible, or actively dangerous the rest of the year.

That question has much stranger answers.

Salar de Uyuni, Bolivia: the place that only exists in winter

Salar de Uyuni in Bolivia is the largest salt flat on Earth, nearly 4,000 square miles of it at 12,000 feet on the altiplano. For most of the year it is a white plain. Atlas Obscura has reported that once the rains stop in April it becomes so uniformly featureless that it is used — along with a handful of other salt flats, deserts and ice sheets — to calibrate the optical sensors on orbiting satellites. Technicians point sensors at it precisely because nothing is there.

Then the wet austral summer arrives, which is the northern winter, and a thin layer of water settles on top of the salt crust. The flat becomes a mirror roughly the size of Northern Ireland. The horizon disappears. People photographed standing on it appear to be standing in the sky.

That is a December-to-March phenomenon. Go in July and you are looking at a car park.

While you are there: the Great Train Graveyard sits on the outskirts of Uyuni, more than a hundred British-built steam locomotives from the early twentieth century, abandoned and eaten by salt wind. No fence, no guards. They were picked over and vandalised long ago, which is somehow the point. The salt flat itself has entries for the tours out of Uyuni, San Pedro de Atacama, and Tupiza.

Nearby, on the same high desert circuit: Laguna Colorada, a red lake at 4,000 metres full of rare flamingos; Laguna Verde, emerald and emphatically not for swimming; and the Salvador Dalí Desert, named for the obvious reason.

The Salton Sea, California: the desert that would kill you in July

The Salton Sea sits in the Southern California desert, and summer there is genuinely hazardous. Winter is the season it comes alive — which is not a figure of speech. Slab City, the off-grid community on an abandoned Navy base near Niland, swells by thousands of people every winter as snowbirds arrive in RVs and leave again before the heat.

At its entrance stands Salvation Mountain, 150 feet wide and 50 feet tall, built by Leonard Knight out of adobe and donated paint after his attempt to launch a hot air balloon carrying a message about God's love failed to get off the ground. He worked on it for over twenty years and lived out of his truck while doing so. In 2002 a US senator entered it into the Congressional Record as a national treasure. Knight has died; visitors still bring paint.

And the Salton Sea itself is one of the strangest landscapes in North America — an accidental lake created by an engineering failure, once marketed as a desert Riviera, now a shoreline of dead fish, barnacles and salt. The visitor centre displays fatty deposits formed during mass fish die-offs, labelled Salton Sea Hush Puppies. Scientists who once called it an ecological wasteland now describe it as a crown jewel of avian biodiversity, both things being true at once.

The wider Salton Sea collection includes geothermal mud pots that burp and gurgle, the domed rocks of Obsidian Butte, Bombay Beach, and a museum devoted to a sea that should never have existed. Calipatria alone holds seven entries.

Go between November and March.

The Atacama, Chile: the driest place on Earth

The Atacama in northern Chile is dry enough that things simply do not rot, rust, or wash away. That is the whole reason to go.

For more than thirty years a man named Rodrigo Martinez has walked out into it looking for meteorites, and the collection he has built is now among the largest in the world. The Meteorite Museum in San Pedro de Atacama houses it in a geodesic dome on the edge of town, arranged chronologically, and — unusually — visitors are allowed to touch the exhibits. You can put your hand on something that fell out of the sky. The aridity is why they survive on the surface long enough to be found at all.

North of there are the nitrate towns. Until 1909, Chile had a near-monopoly on sodium nitrate — white gold, valuable because it could be used as fertilizer, as explosive, or as rocket fuel. Whole communities of workers from South America, Europe and Asia formed around the saltpeter works at Humberstone and Santa Laura, developing what UNESCO would later describe as a distinct urban culture with its own language and customs.

Then two German chemists, Fritz Haber and Carl Bosch, worked out how to fix nitrogen industrially. By 1960 the towns were completely abandoned. Atlas Obscura's photo essay from inside Humberstone captures what the desert preserved: children's toys made from wire and tin cans, cooking stoves, a warning poster for camp employees, rows of workers' houses standing wall to wall.

Every one of these ghost towns can be visited, though one comes with a warning. Chacabuco was used as a concentration camp during the Pinochet regime, and the perimeter beyond its marked paths is still seeded with landmines — visitors stick to the trail and go with a guide.

San Pedro de Atacama has seven other entries including ALMA, one of the most advanced radio observatories on Earth, a bookshop in the middle of the desert, and Pukará de Quitor, a 12th-century walled fortress town that predates San Pedro entirely.

Kolmanskop, Namibia: the town the desert is eating

In Namibia, Kolmanskop was a diamond town. In 1908 a railway worker named Zacharias Lewala picked up an unusually shiny stone and showed it to his supervisor, and within a few years the sand was producing diamonds that could be gathered by hand. The settlers built ballrooms, casinos, theatres, an ice factory, and the first X-ray machine in the southern hemisphere — partly, it is said, to check whether workers were swallowing the merchandise.

More than 2,000 pounds of diamonds came out of the sand before richer deposits were discovered near Oranjemund in 1928, pulling miners south and starting the town's slow death. Within fifty years of its founding the town was empty. The Namib has been moving in ever since, and the buildings now stand with dunes pouring through their doorways up to the windowsills.

Atlas Obscura featured it years ago and the description still holds: poor in minerals, rich in aesthetic mementoes. Access requires a permit, which can be purchased at the gate or online.

And a broader principle

Atlas Obscura's list of 22 unusual things in the desert is the argument in miniature — meteorite collections, hand-dug tunnels, nuclear test sites, land art visible only from above, and a tradition of leaving tea kettles at a remote junction in Death Valley.

Deserts keep things. Low humidity means slow decay, and low population means nobody clears anything away. That is why the strangest human leftovers on Earth are mostly in hot, dry places — and why the northern winter, when those places drop from lethal to merely warm, is the correct time to go and look at them.

Not the beach. The other thing.