I have a world I am building that is similar to ours, and is set in the height of the Roman empire era. The main difference is that the winter is half the year and full rotation of seasons is 18 months:

  • Spring 3 months
  • Summer 3 months
  • Fall 3 months
  • Winter 9 months

The winter looks like the one in northern USA/ southern Canada: heavy on and off snowfall, and mostly freezing temperatures for the majority of the season.

What would society have to be like to survive this type of world? Would this level of society be able to store enough food for these long winters?

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    $\begingroup$ You might want to take a look at countries in the extreme North. E.g. as you mention Canada; but also Norway, Sweden (amazing there, half the year it's super hot, half of it you almost die of the cold), Russia/Siberia $\endgroup$
    – dot_Sp0T
    Jan 16, 2017 at 18:46
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    $\begingroup$ If winter is a lot longer than spring or autumn, then your planet must have a highly eccentric orbit, and so summer will be a lot shorter than spring or autumn. Try 1 mont instead of 3 months for the duration of summer. $\endgroup$
    – Mike Scott
    Jan 16, 2017 at 18:47
  • $\begingroup$ Define freezing in your world! Freezing is only 32F scientifically, which is completely survivable. Here in Wisconsin it get down to 0F and windchills below that, I am still here. How cold is the coldest temperature. $\endgroup$
    – cybernard
    Jan 16, 2017 at 18:47
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    $\begingroup$ (Ice) fishing, penguins, and polar bears are definitely available most of the year. So you would not have to store ALL your food. This situation depends mainly on the preservative available, many people used large quantities of salt to preserve their food. Also ice houses, kept food frozen, and safe for many months. As long as the leaders built, and maintained warehouses, and planned for 2x-3x extra food in case the crops were not as good some years. The eskmo, actually build their houses out of ice because its all they got. $\endgroup$
    – cybernard
    Jan 16, 2017 at 19:02
  • $\begingroup$ How similar to our world? The extreme north and south are cold all year long, and near the equator weather is good all year long. Does this happen in your world? If not, to what degree is it different? $\endgroup$
    – cybernard
    Jan 16, 2017 at 19:09

1 Answer 1


The climate you want is Estonia

Here is the link to Tallinn, Estonia's climate chart on Wikipedia.

The weather here meets your requirements, more or less. Pro-rating the months from 18 down to 12, you want 6 months of winter, and 2 each of spring, summer, and fall.

Tallinn's summer (Jul and Aug) are the only two months with average daily temps over 15 C. The spring (May, Jun) are the only other months that have more than 7 hours of sunshine a day, on average. And then the fall are the only other months where average temps are above 5 C. The rest of the year is winter. April doesn't quite fit this scheme, since the average low is above freezing and it is relatively sunny, but the other 5 months of winter are pretty wintery. There are 87 days of snowfall; about half the days of the 6 winter months.

The key to Estonia is that it has a maritime climate that keeps the maximum lows from being too extreme. The February average low is a balmy -7C. There are several cities that have much hotter summers, yet still have a colder winter. Examples would be Chicago (-9C in January) and Beijing (-8C in January). This means that in Estonia you can grow temperate tree and bush crops to help diversity the diet.

Agricultural production of the Baltic

To figure out what kind of civilization you would have, you have to look at what sort of agriculture they have. You can look up the agricultural output of Estonia, and similar countries like Sweden, Finland, and Latvia. Here is a detailed break down of crop production challenges in those climes.

For grains and high calorie products, the Baltics states were a traditional grain-growing region supplying food to the urbanized parts of northern Germany, the Low Countries and England. In more modern times, there is much potato and sugar beet production.

The south Baltic coast is a big center for apple production, although the summers there are a little warmer than in Estonia. Plums and currants are other fruits that can handle the cold well. Leaf vegetables do well in northern climes, like lettuce and especially brassicas like broccoli, turnips, cabbage, and (eww) brussel sprouts. Onions can also mature in the short growing season.

For fiber crops, flax used to be grown in great abundance. Flax growing is much reduced worldwide, as cotton replaced flax, but linen was popular in medieval Europe and would be in your world. Wool of course, is also popular in cold climate. Oilcrops are rare; butter would be the primary fat product. Canola oil, or rapeseed, was not grown widely in ancient times. It is a product of China, but in the last century has become the primary vegetable oil produced in the Baltic.

As far as animals go, cattle, sheep, and goats all survive well in such cold climates. Some of the best growing crops in such climates are fodder crops, like clover and grasses. This can be seen in the US, where the places with the coolest summers (Wisconsin, New England) are usually dairy producing states as opposed to grains, corn, or soy that thrive with warmer summers. Your land will probably be animal husbandry oriented, with lots of shepards and mixed agriculture/husbandry.


There is plenty of agricultural produce available to support large cities in this type of environment. I would imagine the warmer bits would have more fruit trees and grow grain in the longer summers, while in the colder climes, grass and clover would be grown and baled as hay for use with sheep and cattle.

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    $\begingroup$ It is fairly similar, but with some variations, for most of the Baltic and Nordic countries, but you are otherwise spot on. $\endgroup$
    – Mrkvička
    Jan 16, 2017 at 19:26
  • $\begingroup$ Classical Roman agriculture relied on grass that grew all winter, which farm animals ate all year round. There is a theory that the fall of the Western Roman empire was caused by climate change (colder) leading to agricultural collapse. Keeping animals in barns and feeding them preserved vegetation over winter was a later development which made Northern agriculture possible.. $\endgroup$
    – nigel222
    Jan 16, 2017 at 20:34
  • $\begingroup$ @nigel222 I don't know what the point of this comment is. I know that Roman agriculture is different, which is why I described the general agricultural conditions that an Iron Age civilization in a northerly environment would use. This civilization would not use the same agricultural system as the Romans. Agreed. $\endgroup$
    – kingledion
    Jan 17, 2017 at 2:33
  • $\begingroup$ @kingledion Question says "set at height of Roman Empire". If precise historical accuracy is desired, then agriculture in this climate depends on methods as yet to be invented and is therefore impossible. If not historically accurate, there is no reason why alt-history Romans couldn't have used barns, hay and silage. But in our history, they didn't. $\endgroup$
    – nigel222
    Jan 17, 2017 at 8:57
  • $\begingroup$ @nigel222 That is an excessively narrow interpretation. Obviously the general Roman technology level would be maintained, while specific technologies would be modified to meet the environment. $\endgroup$
    – kingledion
    Jan 17, 2017 at 14:18

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