The desert at night: cold and darkness

Every warm object gives off heat as invisible radiation – the ground, the rocks and you yourself. Water vapour and clouds in the air catch part of this radiation and send it back. In humid regions nights therefore stay milder. In dry, clear desert air this protection is missing, and the ground and air cool quickly after sunset.

That is why large differences between day and night are typical in deserts. How large they are depends strongly on region, altitude and season. High-altitude deserts and deserts in winter can even have frost at night.

Then there is conduction: if you lie on cold sand or rock, heat flows directly from your body into the ground. A sleeping pad or another insulating layer interrupts this path. In a desert night it is often more important than an extra blanket on top.

Sweaty clothing is the hidden enemy. During the day you sweat even if you hardly notice, because the sweat evaporates quickly in the dry air. But if moisture stays in the fabric, it chills you further in the evening. So change into dry clothes before the cold sets in, or let your clothing dry while the sun is still warm.

A warm layer, a hat and a sleeping pad belong in every desert pack, even for a day trip. A vehicle breakdown or a sprained ankle can unexpectedly keep you out overnight. An emergency blanket can help additionally in an emergency but does not replace proper clothing.

The camp should be slightly raised, outside wadis and hollows and if possible sheltered from the wind. The coldest air collects in hollows at night, and wadis can turn into raging torrents during thunderstorms – even if not a single raindrop falls on you.

In hot regions some people prefer to walk at night, because they sweat less and save water. That can make sense but brings its own risks: rocks, holes and drop-offs are hard to see, navigation is harder and groups lose each other more easily. Night walks therefore belong only on known routes and never alone in unfamiliar terrain.

Take a headlamp and spare batteries, plus a compass. The night sky can help you hold a direction but does not replace practised navigation. As a group, keep visual contact, agree on fixed breaks and count heads regularly.

Hypothermia can happen even after a hot day. Shivering, clumsiness, slurred speech or confusion are warning signs. Then it helps to insulate the person from the ground, swap wet clothing for dry, shield them from the wind and wrap them up warmly. If their condition gets worse, call the local emergency number (112 in the EU).

Many desert animals are active at night and seek shelter in dark corners during the day. So shake out shoes, clothing and sleeping bag before using them and do not reach blindly under rocks or into crevices. This text deliberately does not identify animal species – ask locally which animals live there and how to behave.

A vehicle breakdown in arid regions is a topic of its own. In general: a vehicle is much easier to find from a distance than a single person, and it offers shade by day and wind shelter at night. Anyone planning a route leaves the way and expected arrival time with someone beforehand.