I'm writing an alternate timeline about a new country in Western Europe called Biscay. Biscay has a broadleaf forest biome and has many mountains along its southern border. Biscay is roughly equal to modern Poland in size. The Loire and Garonne river pass through Biscay.

Landed Biscay

Based on its location and the climate of neighboring countries, what average temperatures would Biscay have throughout the year. For reference, these are the average temperatures of Spain and France.

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    $\begingroup$ The average temperatures in Spain and France are completely irrelevant. The average temperature of Spain includes Andalusia, and the average temperature of France includes the Cote d'Azur. What is of interest are the average temperatures of La Coruna, Bilbao, Bayonne, Bordeaux, and Nantes. And note that your fantasy country extends over 8 degrees of latitude, so that there will be significant differences between the southern and northern parts. Also note that there will be significant differences between the coastal western part and the continental eastern part. $\endgroup$
    – AlexP
    Dec 17, 2023 at 1:28
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    $\begingroup$ I can definitely confirm AlexP's words by experience, Bretagne is very often a damp and fresh place in France (#OceanicClimate), while south-east towns like Montpellier is hot enough to limit yourself to shirts all year... Excepted a good raincoat but no umbrella for the storms (#MediterraneanClimate). In Alsace and the Alps, the climate is rather dry, but you can have quite different temperatures from season to season (#ContinentalClimate). You'd probably vastly improve your country's climate if you think more locally 🐶. $\endgroup$ Dec 17, 2023 at 2:18
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    $\begingroup$ It would essentially be the same as equivalent areas in France in our world — same latitude, same ocean to the west, same continent to the east. The climate of western France would change, since it would no longer border an ocean. $\endgroup$
    – Mike Scott
    Dec 17, 2023 at 8:05
  • $\begingroup$ wasn't a country in the bay of biscay a meme like a year ago? $\endgroup$
    – OT-64 SKOT
    Dec 18, 2023 at 4:42
  • $\begingroup$ VTC:Needs More Focus for the phrase "Throughout the years." Note that for the sake of worldbuilding: it's an horrific oversimplification, but climate around a specific latitude is generally the same ignoring variations in altitude and large bodies of water. That's just the way planets work, so there isn't much of a mystery here. Draw latitude lines through France and use the western equal-latitude border cities for the western border of Biscay and the eastern equal-latitude cities for the eastern border of Biscay. $\endgroup$
    – JBH
    Dec 21, 2023 at 4:43

1 Answer 1


Roughly the same temperature as real-world France

... Just a bit warmer.

France's climate is dependent on a good part of its long western coast. Western winds from the Atlantic ocean brings rains, and therefore soften the climate, bringing it freshness. So creating this landmass to its west will "transfer" this rain and softness from France to this new region.

Now why do I say it would be a little warmer than France?

  • First, Biscay is on average on a lower latitude than France. So temperatures would -on average- be warmer than France.
  • Then because you don't have a direct access to the Mediterranean sea, which normally helps a little in softening France's southern climate during winter. You're more likely to have a semi-arid climate in the southeast region instead.

Final note

I do have to stress out that I gave only the general idea as you "only" requested for average temperatures. However, to work effectively the temperatures of your country you need to look at a much higher level of details. Check out the Köppen-Geiger Climate classification map just for instance : You'll see that climates on a local level vary a lot even inside a country like Spain. This imply both wide changes from region to region, but also from season to season... And from day to night.

So in order to have an actual accurate depiction of your country's climate, you should work from region to region, using the land topography (mainly mountains, but also arability) to determine what climate goes where.

With more detailed climates you'll improve a lot your world's fine strengths and develop strong tales and trivia. For instance, you would be able to tell that the North is so "freezing" and rainy in winter that no southern mail carrier wants to work there.


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