Note: an edit has been made to the main question at the bottom

A couple of years ago, I had a worldbuilding project which I have recently revived.

I was relatively new to worldbuilding back then, and I made the terrible mistake of drawing a map of my planet before deciding axial tilt.

Now that it has been reborn, I am applying my much better worldbuilding skills to the project to give it a new and more plausible feel.

Since I already had a map of biomes, I divided the width of the page the map was on by 18 to determine lines of latitude (One for every 10 degrees).

Using the biome map, I denoted that the absolute minimum figure for the latitudes of the tropics must be 40 degrees north and south., meaning the axial tilt of the planet is 40 degrees.

Therefore, the latitudes of the polar circles would be 50 degrees north and south.

But that figure conflicts with my map. The environment only starts to change to tundra at around 20 degrees north and south, which is already halfway inside the polar circles.

So, my question is: Is it possible for the climate in the warmer half of each polar circle to be temperate, and if so, how would I do it?

  • 4
    $\begingroup$ Did you know that earth had warm periods and ice ages where what temperate regions were differed by a bit? $\endgroup$
    – Raditz_35
    Jun 13 '18 at 16:33
  • 1
    $\begingroup$ Informative but non-duplicate question: worldbuilding.stackexchange.com/questions/75580/… $\endgroup$ Jun 13 '18 at 16:36
  • $\begingroup$ This is an excellent, fact-based question that a search engine readily answers with historical examples. $\endgroup$
    – user535733
    Jun 13 '18 at 16:38
  • $\begingroup$ If you want axial tilt of 40 degrees, that would mean long and harsh winters for most of the planet. So much for tropics at 40 degrees latitude. On the other hand, boreal forests can extend very far toward the poles. $\endgroup$
    – Alexander
    Jun 13 '18 at 17:04
  • $\begingroup$ @Alexander If the axial tilt is 40 degrees, then the tropics must be 40 degrees. That's how major lines of latitude work. $\endgroup$
    – SealBoi
    Jun 13 '18 at 17:45


In Earth history there was a time when tropical plants grew at the poles. So, give the right combination of atmosphere composition, condition and solar irradiation, and it can happen.

Useful Triassic Period citation:

"There were no polar ice caps, and the temperature gradient in the north-south direction is assumed to have been more gradual than present day. "

  • $\begingroup$ @user535733, added that in the answer, thanks $\endgroup$
    – L.Dutch
    Jun 13 '18 at 16:48

The Gulf Stream is a very important aspect of the global climate that helps maintain the climate of locations like the British Isles and Scandinavia via the North Atlantic Current.

A noticeable effect of the Gulf Stream and the strong westerly winds (driven by the warm water of the Gulf Stream) on Europe occurs along the Norwegian coast. Northern parts of Norway lie close to the Arctic zone, most of which is covered with ice and snow in winter. However, almost all of Norway's coast remains free of ice and snow throughout the year. Weather systems warmed by the Gulf Stream drift into Northern Europe, also warming the climate behind the Scandinavian mountains.

Your planet could have a series of ocean streams that move warm water (and thus air) from the part of the planet closest to the sun to the poles. It might take some finagling to make a plausible continent/ocean shape, if you care to, but I think this is a realistic way to say that part of the poles would be temperate. The other half of the pole could be blocked off from the effects of the warm weather by particularly high mountains. Look at how desolate the east side of the Rocky mountains is compared to the west.


In addition to other answers that discuss the Gulf Stream and cyclic climate change, there is a specific casethat come to mind.

Axial Tilt

If Earth were tipped on it's side, like Uranus, then the poles would likely never have ice on them, even if the points furthest from the solar plane did.

  • $\begingroup$ A problem with your answer: the geographic poles are fixed. What you're talking about in "geomagnetic reversal" are the magnetic poles, which are something rather different. Magnetic poles do indeed move, but they have little to no direct relevance to climate. $\endgroup$
    – Palarran
    Jun 13 '18 at 21:39
  • $\begingroup$ Good point. Fixed that. $\endgroup$
    – CaM
    Jun 13 '18 at 21:46
  • $\begingroup$ Another issue : the question specifies what the axial tilt of the planet is. Although it is higher than on Earth, so your answer is kind of relevant or at least can be rewritten to be. $\endgroup$ Jun 13 '18 at 22:14

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