I am coming up with a new planet idea inspired by One Piece. I'm imagining a planet with the same mass, volume, and sunshine as Earth. The difference is that it is mainly an ocean planet. There are no large continents. Instead, there are thousands of islands spread across the planet that are roughly the size of Jamaica. The one exception is a huge mountainous continent in the center. Along the entire equator is a huge landmass that stretches 500 km both north and south. This landmass is filled with mountains but it also has many plateaus and a few jungles plus rainforests. This equatorial continent effectively cuts the planet in two; leading to two completely separate oceans. There is almost no land at the poles.

So given these conditions, what is the expected climate of this world? I think there would be conditions similar to the Pacific Ocean in both halves but the climate on each island could vary.

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    $\begingroup$ Humanity knows about the climate of one habitable world - Earth - and we have trouble predicting tomorrow's climate, and you want a hard-science analysis? Answers that fail to conform to its rules are under threat of deletion. Answers are required to provide mathematics and citations to prove the answer. I don't know what you expect us to draw from to prove the climate of an imaginary world when we have only one datapoint to work with. Maybe your expectations are a bit high? Consider science-fiction and this answer. $\endgroup$
    – JBH
    Commented Mar 20, 2023 at 2:07
  • $\begingroup$ You haven't provided nearly enough detail to hope for a hard science answer; how are these Jamaica-sized islands distributed? What shape does the equatorial continent take? Where are the continental shelves? Any insland seas of note? Mountain ranges? $\endgroup$
    – rek
    Commented Mar 20, 2023 at 16:50
  • $\begingroup$ ".. a huge mountainous continent in the center". Of a continuous line? Or of a sphere? Where, pray tell, is that, exactly? :D $\endgroup$
    – Joachim
    Commented Mar 21, 2023 at 10:30

1 Answer 1


Not terribly different from that of the Earth

Climate is mainly determined by three factors: Sunlight, rotation and wind.

The farther you are from the equator, the less sun you get, and the greater are the seasonal variations, with areas beyond the polar circles experiencing all-day sunlight in summer and all-day darkness in winter. The inclination of your planet determine how far the polar cicles are from the poles; with zero inclination, they coincide with the poles, and with 90 degrees inclination, they coincide with the equator. You need to set an inclination for your planet before anything precise can be said about its climate.

Your planet's rotation determines the length of days and nights and hence the difference between day and night temperatures. The rotation is also responsible for the coriolis effect that drives the planet's major wind systems; the faster the rotation, the stronger the winds.

Your planet will have the same major wind systems that we see on Earth: the Polar Easterlies, the Prevailing Westerlies, and the Trade Winds (though their direction will be reversed if your planet rotates the opposite direction). Se illustration for their direction. As you can see, they aren't much affected by continents or oceans; in fact, on your planet, they should be more 'pure' in the sense that there are no large landmasses to disrupt them. Since there is very little wind near the equator (know as the calm zone), your equatorial continent will have very little effect.

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  • $\begingroup$ I should add that if your planet's orbit is elliptic, it will also affect your climate, with seasons being more extreme in one hemisphere than in the other, as on Mars. $\endgroup$ Commented Mar 21, 2023 at 15:11

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