Purely geography only. I'll break down into points. What I'm giving you below is just to narrow down the possibility, but otherwise, quite arbitrary.

Assuming a large archipelago of islands existed on real Earth at one point in the geologic history.

The combined area of the islands is let, say, half the size of Indonesia (if size has any relevancy at all).

Situated approximately at the center of the North Atlantic Ocean, east of the Bahamas.

Its northernmost point is at the same latitude as Charlotte, North Carolina. Its southernmost point is at the same latitude as Port-au-Prince, Haiti. Its westernmost point is at the same longitude as Port of Spain, Trinidad and Tobago. Its easternmost point is at the same longitude as the easternmost point of Brazil.

The island has elevations and terrains no different than typical islands in the Caribbean.

The largest island is no bigger than Cuba. Most islands are less than 100 km^2, and the archipelago contained thousands of them. The islands are relatively tightly clustered.

So let's get to the question, what would be the possible climate description of this archipelago? Feel free to make assumption about the terrain factors.

  • $\begingroup$ I found Atlantis! $\endgroup$ Apr 8, 2016 at 14:16

2 Answers 2


Size does matter. With enough size, you can justify whatever your story needs:

  • If there is a Gulf Stream and they are in it, expect a reasonably warm, very wet climate.
  • If the positioning of the islands changes currents in a major way, e.g. by blocking the Labrador Current, one would have to ask where the warm water goes. The south side of your islands could get much warmer, or the current goes elsewhere and it gets much colder.
  • $\begingroup$ Thank for pointing out, I should've make a visualization as it's hard to imagine. By the way, from the latitude/longitude I gave, most of the islands weren't exactly blocking the major oceanic current. It located approximately at the center of the current cycle, leaning a bit south, somewhat closer to North Equatorial Current. I'm not quite sure what would the land climate be in the middle of the Atlantic, as there's no islands there that I could draw example from. $\endgroup$
    – JSWorld
    Apr 8, 2016 at 6:09
  • $\begingroup$ @JSWorld, the island would probably be big enough to have a continental shelf (instead of a volcanic high island). That will affect the entire global climate ... $\endgroup$
    – o.m.
    Apr 9, 2016 at 6:40

I generally agree with o.m.'s answer. The northern half would probably be a Koppen Cfa climate like much of the SE USA. That is, warm-to-hot summers, very mild winters, and no pronounced dry season.

The southern half would probably have some more monsoonal and savanna like climates, with hot summers, warm winters, and with at the most several months with little or no rain. That is, basically like Cuba, Hispaniola, and Puerto Rico.

Check out Koppen climate classification on Wikipedia for details.

Hope this helps.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .