One of the main characters in my book series is from an ecumenopolis (planet-city, similar to Coruscant from Star Wars) that is climate controlled to be wet and temperate all year round. Rainfall is completely constant, and temperature is the exact same each day, changing only every month. Here is the climate chart below:

enter image description here

NOTE: I forgot to change "in" to "mm" before I screenshot this, so the 1041 is in mm, not freedom units.

Given that the character in question is human and has lived their whole life in this environment, how would well would their body acclimate to being thrust into somewhere with extreme weather (such as high mountains, a desert, or deep jungle)?

  • $\begingroup$ They would acclimate easily. English people live in a very mild climate, with little variation between summer and winter; and yet they have established flourishing colonies all over the world. People from equatorial countries, with almost no climatic variation over the year have moved to countries with great variation between summer and winter and have had no trouble living there; there are people of equatorial African descent living in Montana, in Sweden, even in Russia. Arabs, who naturally live in a constantly hot climate, have moved to cold countries, to wet countries, etc. $\endgroup$
    – AlexP
    Mar 11, 2021 at 23:41
  • 2
    $\begingroup$ I think it’s important to mention more requirements, eg. how extreme an environment, and how well the person needs to be acclimated. $\endgroup$
    – Enthu5ed
    Mar 12, 2021 at 0:05
  • $\begingroup$ I was going to say ... 1000 inches would cause some problems. $\endgroup$
    – user458
    Mar 12, 2021 at 6:06
  • $\begingroup$ @AlexP - What part of England do you live in? There are parts of England where lakes can freeze over in the winter and road surfaces ooze tar in the summer. $\endgroup$ Mar 12, 2021 at 12:57
  • 1
    $\begingroup$ @chasly-supportsMonica: I said "little" variation, not "no" variation. Yes, I know that is occasionally snows in England. The Canary Islands it is not; but then, the people of the Canary Islands do live in an eternal spring, and would be an even better example! $\endgroup$
    – AlexP
    Mar 12, 2021 at 15:46

5 Answers 5


Acclimation would happen pretty quickly, I tell you this out of personal experience: some years ago I moved North by about 2500 km, to a colder climate.

The first winter was chilly and long as I never experienced, and the first summer was what for me was always mid spring, what I called a constant "I would, but I can't": I was never able to wear a t-shirt nor shorts the whole season. Then the following years here I am, enjoying a warm day which in my birthplace would qualify as "wear coat and scarf, else you will get sick", and going out cycling even when the rivers freeze.

  • $\begingroup$ It ain't cold if you can't freeze to death. It's not actually a winter until it's colder than -15C. And it's not really cold until it's colder than -25C. $\endgroup$
    – DKNguyen
    Mar 12, 2021 at 6:06
  • $\begingroup$ @DKNguyen and it's not summer until the asphalt becomes rubbery :D $\endgroup$
    – L.Dutch
    Mar 12, 2021 at 6:13
  • $\begingroup$ I think I've only see that once. $\endgroup$
    – DKNguyen
    Mar 12, 2021 at 6:31
  • $\begingroup$ @DKNguyen, when I was a kid there was a day in summer which was so hot that the speed hand in the dashboard of my father's car bent under its own weight and got stuck there. $\endgroup$
    – L.Dutch
    Mar 12, 2021 at 13:04
  • $\begingroup$ Don't leave pets and kids in the car, folks. $\endgroup$
    – DKNguyen
    Mar 12, 2021 at 19:01

A person's tolerance for cold is not the same as their preferences. In a scientific/biological sense, "tolerance" generally means suitability, or at least doesn't motivate extreme behaviors like hibernation and migration. In a word, it's what one can reasonably expect individuals to survive.

Humans clearly have adapted behaviors to survive far extremes, as was evidenced long before modern comforts. I don't think acclimation, as a proxy for preferences, matters as much as you might think. It becomes more mental than anything else, made better or worse by circumstances. For example, if you are stranded on Hoth with bad company you probably will have a hard time enjoying yourself, especially compared to being on your honeymoon in Siberia with your cold-loving wife.


Quite easily, for the greater part.

Acclimatization is the ability and act of adjusting to a changed environment.
This is achieved by 4 means:

  1. Short-term automatic physiological changes: (sweating, shivering, heartrate, breathing, goosebumps, etc)
    The body adjusts its normal functions, within the normal range for those functions, but favoring the new environment. These are the quickest changes to happen, they occur completely automatically, and take effect within a span of seconds to hours.
    Things like constricting bloodflow to the extremities to retain heat, sweating to increase evaporative cooling, etc. Your megacity dweller will do these automatically and effectively. The maximum ability to adjust will be somewhat subject to the body's range of ability to do so, which will initially be somewhat reduced. Your dweller will not have experienced these before to this extent, and may feel discomfort greatly in excess to the actual situation.
  2. Longterm physiological adjustment: (tanning, oxygen transport, vascular changes, renal changes, protein reconfigurations etc.)
    These are also automatic changes, but that actually alter the body. They take from many hours to several days to occur.
    There are a great many ways that the body can alter itself to better cope with an altered environment. The skin can tan, releasing more melanin to shield it from solar UV rays. The vascular system in the extremities can grow to encourage better bloodflow in the cold, and in the lungs can increase bloodflow to the alveoli of the lungs, allowing more oxygen to be collected. The bloodcell producers can increase the amount of red blood cells in the system, allowing more oxygen transport. The kidneys can alter their handing of blood salt levels in response to water surplus, or shortage. Even the very shape of some proteins in the body can change to alternate configurations, that are slightly less efficient at their job but exhibit better resistance to thermal and UV breakdown!
    Note that al of these changes require that the body work at it, expend resources to grow new structures or alter chemical balanced. All of these induce stress on the body, and consume resources to achieve. And time, sometimes a lot of time.
    Your megacity dweller will also do these automatically and effectively, although the required time to adapt may be significantly longer as most of these changes will be getting done for the very first time in their life. Expect a lot of discomfort, even some pain, as the changes occur. A perfect example of this type of adjustment is sunburn, eventually leading to a suntan.
  3. Genetic changes:(not of the individual, of course, but of their race)
    The ability of the body to achieve the changes in (1) and (2) above are defined in its genetics. Not all people are equally capable of adapting to changed environments!
    As simplistic examples: The Inuit have thicker subcutaneous fat deposits, whether they have grown up in a cold environment or not. A black African naturally has a very high melanin concentration in the skin, making adaptation to intense solar UV levels easy. Tibetans have altered lung vascular structures and blood chemistry, giving them an advantage in acclimatizing to high altitude and low oxygen pressures.
    Your megacity dweller might have some such ancestral adaptation advantages, but is more likely to have none if their ancestors have lived in such a city for many generations.
  4. And lastly but definitely not least important: MENTAL outlook.
    Never mind how well or badly the body adapts to the environment, whether it has genetic advantages or disadvantages, the one factor that will make the most important difference is the mental approach of the person.
    Not just attitude and reaction to the changed environment, even though these are of paramount importance, but also in the willingness and ability to acquire new habits, lose old habits, and to mentally adjust to the new environment.
    Sadly, I believe it is in this category where you megacity dweller is most likely to stumble and fall. They will have been "pampered" throughout their entire life, accepting that the environment is intrinsically pleasant, never attacking the person. They will have to learn that, sometimes, the person needs to adapt to the environment, not the environment get adjusted to coddle the person.
    Example: The utter shock and denial seen in an American tourist to Africa, who discovers that not only is the aircon not set to comfortable temperatures, but that there is no aircon in 99% of private dwellings.

They will of had practice with extremes of heat and cold even on your climate controlled planet.

So long as humans can sweat, and shiver, and their blood vessels still constrict in the cold, and dilate when hot, and all the other things we do in different temperatures, we'll be fine.

Even in a controlled city with perfect climate you'll still have exposure to hot and cold outside the survivable / comfort range to test these responses:

  • The supermarket fridge isle will still make people shiver.
  • People will have to still their hands into freezers to extract food from time to time.
  • People will have spas and saunas
  • People will still cook, or work with machinery that generates heat.
  • People can still be outside in the rain / swimming and get cold from evaporation.
  • Physical exercise will produce heat, and you need minimum exercise to stay healthy.
  • If nothing else they need to reproduce, and that typically tests heat dissipation measures including sweating.

If you put someone used to climate control in the jungle or desert or artic; they'd grumble about it. They'd be short tempered and frustrated. But they'd survive.

I'm used to 45C summers and 15 degree C winters. Winter daytime may need a light cotton jacket if the sun isn't out. I had to travel to Canada for work and felt my first ever -10 C. I grumbled for days, but my body survived.


how would well would their body acclimate to being thrust into somewhere with extreme weather (such as high mountains, a desert, or deep jungle)?

These places are not created equal. Perhaps more importantly, the acclimatisation issues are not necessarily related to the changeability or kind of climate a traveller is coming from.

With high mountains (defined as >2500m ASL equivalent on Earth), the principle issue is altitude sickness, and acclimatisation to altitude will likely take a few days. Trying to charge off and perform energetic physical exercise at high altitude can kill you, so at least part of the acclimatisation process is not doing anything stupid. Tendency to engage in stupid activities and die of ignorance is common across human cultures.

The NHS says:

  • avoid flying directly to areas of high altitude, if possible
  • take 2 to 3 days to get used to high altitudes before going above 2,500m
  • avoid climbing more than 300m to 500m a day
  • have a rest day every 600m to 900m you go up, or rest every 3 to 4 days
  • make sure you're drinking enough water
  • avoid smoking and alcohol
  • avoid strenuous exercise for the first 24 hours
  • eat a light but high-calorie diet

Clearly, acclimatisation will depend partially on the person's lifestyle ahead of time, partially on what they're expecting to do when they get to their destination, and partially on whether they can follow basic instructions.

Similarly with very hot climates, failing to take time to acclimatise can kill. This is perhaps more important, as acclimatisation takes a couple of weeks and requires active engagement in the process. The US Army, for example, has an obvious interest in being able to put people into hot places and have them carry heavy things about without keeling over with heatstroke. From this guide:

Generally, about two weeks of daily heat exposure is needed to induce heat acclimatization. Heat acclimatization requires a minimum daily heat exposure of about two hours (can be broken into two 1-hour exposures) combined with physical exercise that requires cardiovascular endurance, (for example, marching or jogging) rather than strength training (pushups and resistance training). Gradually increase the exercise intensity or duration each day. Work up to an appropriate physical training schedule adapted to the required physical activity level for the advanced military training and environment.

Jungles do not necessarily have either of these problems (though consider the existence of cloud forests) and so acclimatisation issues are more about personal discomfort and following advice to stay healthy, rather than dropping dead because you couldn't skip your morning run (though the local wildlife could still make it fatal, but you can't really become acclimatised to being eaten).


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