I have a world I've been developing whereby the entire world is locked in a cycle of perpetual winter. The "seasons" still exist but are merely a spectrum of mild cold ranging toward horrific winters. More or less it is the Antarctic but across the entire surface of the planet.

Inhabitants have created societies by living in the vast network of caves throughout the rocky surface. Geothermal energy has been harnessed to power and heat these cities. Magic in this world is normalized and minimal. There are a few artifacts of vast power but mostly magic is confined to everyday practical use (minor cantrips for household chores, ward off diseases, etc). The individuals in these cities can and do travel overland to trade, make war, pass along news.

That said, I am curious if there are real world fabrics or processes of weaving fabrics that could be used with the technology available late medieval to a early renaissance society that would be effective at warding off such extreme temperatures. The fabrics ideally would be as light weight as possible.


  • As stated above the temperature range would be -18 F (-27.7 C) in the Summer down to -76 F (-60 C) in the Winter months.

  • The Climate will vary across the surface of the planet with some
    areas experiencing wetter snowier climes and others drier

  • The fabric ideally will keep the wearer warm enough to survive
    exposed during the day time temps and survive under cover during
    evening temps.

  • The fabric will ideally be as thin as possible so that the wearers
    are able to move, work, unencumbered by massive bulky clothing.

  • The flora and fauna of the world resembles a combination of that found in the Ice Age (Pleistocene) era and that found in the present day Permafrost climates.

  • 1
    $\begingroup$ you are giving no info on which animals and plants are available. How do you expect us to choose one? As it is a fictional world you can come with anything you like, even a sheep growing goretex on his outside $\endgroup$
    – L.Dutch
    Apr 20, 2018 at 16:44
  • 2
    $\begingroup$ Mylar, on fire. Thin and warm. $\endgroup$
    – ShadoCat
    Apr 20, 2018 at 17:52
  • 1
    $\begingroup$ "Thin and warm" are difficult to achieve at the same time. Extreme weather clothing usually aiming at being "light and warm", but usually gets bulky. $\endgroup$
    – Alexander
    Apr 20, 2018 at 18:21
  • 1
    $\begingroup$ How warm do these creatures have to be, and what natural defenses against the cold do they have. If you are inhabiting this planet with humans precicely like those on Earth, it will be hard to support them on a planet that is unlike Earth. I would expect evolution to give them a very different set of attributes. $\endgroup$
    – Cort Ammon
    Apr 20, 2018 at 18:40
  • 1
    $\begingroup$ Can we assume that they have been on the planet long enough to adapt to fit their environment at least as well as, say, an Innuit has adapted to their environment? Or are these recent additions to the planet? $\endgroup$
    – Cort Ammon
    Apr 20, 2018 at 18:48

3 Answers 3


Asbestos cloth.

asbestos cloth http://www.yarnmagazine.com.au/category/uncategorized/


... because the ancient Romans were said to have woven asbestos fibers into a cloth-like material that was then sewn into tablecloths and napkins. These cloths were purportedly cleaned by throwing them into a blistering fire, from which they came out miraculously unharmed and essentially whiter than when they went in. While Greeks and Romans exploited the unique properties of asbestos, they also documented its harmful effects on those who mined the silken material from ancient stone quarries. Greek geographer Strabo noted a “sickness of the lungs” in slaves who wove asbestos into cloth... Around 755, King Charlemagne of France had a tablecloth made of asbestos to prevent it from burning during the accidental fires that frequently occurred during feasts and celebrations. Like the ancient Greeks, he also wrapped the bodies of his dead generals in asbestos shrouds. By the end of the first millennium, cremation cloths, mats and wicks for temple lamps were fashioned from chrysotile asbestos from Cyprus and tremolite asbestos from northern Italy.

Asbestos textiles were manufactured from ancient times up until the mid1900s. Of course the main attraction of asbestos cloth is that it is impervious to fire and sparks. It also protects workers against hot air as might be encountered in a foundry. The air pockets trapped between the mineral fibers are excellent insulators; slad wool or mineral wool to this day is used for insulating properties.

If it is a good enough insulator to keep hot air out, it can keep warm air in - next to the body. I found an ad for asbestos clothing from the 1920s that boasted of this property.

The other good thing about asbestos clothing (or slag wool clothing) for this world: it is freaking cold. There will not be silkworms. There will not be cotton. Musk ox will struggle. I am not sure what the humans will find to eat. But they will be able to dig up and refine asbestos into fabric.

  • $\begingroup$ this has the added benefit of creating an avenue for storytelling around illness and asbestos. I wasn't aware that asbestos was used for clothing insulation but as it was used extensively in homes for that exact purpose it stands to reason. $\endgroup$
    – VerasVitas
    Apr 23, 2018 at 17:04

Without knowing what sorts of fabrics are available, there is one way for lightweight materials to be extremely warm: layering.

So long as the outer shell is windproof (to prevent the wind from blowing through the layers of fabric) the multiple layers create insulating layers of trapped air which serve to reduce the amount of heat transfer from the body.

The other caveat is to ensure the person wearing the ensemble does not get wet, either by being exposed to water (i.e. falling in or being splashed by large amounts of water), or by vigorous work leading to sweating. The second hazard can be mitigated by opening or delayering some of the clothing to allow excess body heat to escape.

For a fairly extreme example, when George Mallory attempted to climb Mount Everest in 1924, he was dressed in multiple layers like this, with layers of silk between other layers in order to reduce friction and allow him to climb.

enter image description here

Replica of Mallory's climbing gear

enter image description here

Another view of the replica gear

The layered natural materials used to construct the garments were found to be excellent at trapping air next to the skin.

The outer layer of gabardine was hardwearing and water-resistant yet breathable. But the clothing was also lighter than modern gear - the lightest ever to be used on Everest.

"When exposed to a cutting wind blowing off the main Rongbuk glacier, I found the true value of the Gabardine outer layers. These resisted the wind and allowed the eight layers beneath to trap warmed air between them and my skin.

It has been a three-year project to create the replicas "We both got too hot working on the glacier so we felt that Mallory's clothing would have been more than adequate to climb to the top in, although it would be hard to survive a bivouac near the summit."


So multiple layers of fabric, a hard shell to stop the wind and avoiding exposure to moisture at all costs is the key.


Use an aerogel. They're superlightweight (90% air) and very insulating. This is a Wikipedia article on aerogels. https://en.wikipedia.org/wiki/Aerogel Cork is also good at insulating and natural.

If geothermal energy and a small amount of water magic is harnessed, I would believe that an aerogel would be feasible.

  • $\begingroup$ HOW do you plan to use something brittle for a clothing? youtu.be/kHnen2nSmDY?t=76 $\endgroup$ Apr 20, 2018 at 17:14
  • $\begingroup$ Um. Can you create an aerogel with medieval or renaissance level knowledge or technology? Or are you assuming the limited magic can handle the supercritical controlled drying? $\endgroup$ Apr 20, 2018 at 17:21
  • $\begingroup$ Thank you, @EveryBitHelps. I edited to take your points into concern. $\endgroup$ Apr 20, 2018 at 17:48

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