My friend and I are working on this world called Roia. It shares many terrestrial properties with the real life earth: composition, axial tilt, distance from the star, presence of water, etc. You can consider it an Earth AU. Probably the biggest difference is that Roia has two small moons rather than one large one.

Right now we're working on the climate. I tried to do it by eye, using the Koppen climate classification system. (I've exchanged the labels so that it's easier to understand. Climate Any advice on the accuracy of it? I found it difficult to compare to earth since Roia has so many archipelagos.

These are the ocean and air current respectively as well as the topological map. I hope these will help with determining the the climate of regions. Ocean Current Air Current

  • $\begingroup$ How come there is Hot Desert climate in the same cell as the Temperate and Continental regions? Plus being THAT close to the tundra? $\endgroup$
    – Aezyc
    Feb 27, 2020 at 21:55
  • $\begingroup$ Yeah, that was an oversight. Should convert those to tundra $\endgroup$
    – NukeyFox
    Feb 28, 2020 at 18:35
  • 1
    $\begingroup$ +1 For doing research before asking and then showing us what you've got. This is a pretty quality question. $\endgroup$
    – Zxyrra
    Feb 29, 2020 at 4:27

2 Answers 2


Tip 1: If the current flows towards the equator, it is inherently cold. Even if the water is still tropical, it is cooler than the air it is approaching.

-many of your archipelagos should have dryer regions on one side

-reverse applies to currents moving poleward

Tip 2: Hot deserts are hot because they are in the tropics. They shouldn't be in the same zones as Temperate climates (except in small slivers in lowlands and cold-current coasts.

-Temperate Zones=Cold Deserts

-Tropical Zones=Hot Deserts (unless at a high elevation)

  • $\begingroup$ Noted thanks. The desert on top was a mistake, though I think the desert on the left continent is ok since it's within the 15-30 zone. $\endgroup$
    – NukeyFox
    Feb 28, 2020 at 18:42

I just had a look at your oceans, as I have some knowledge with them....


  • I'm in no way saying that these edits are 100%. Its a best guess situation after a brief look :) If you spot anything funky, I probably missed something or forgot some fact
  • the arrows are pretty badly drawn as I was using my laptop mousepad and the buttons are acting up at the moment
  • I didn't know your bathymetry and where you have any upwelling/downwelling so I made a best guess of what I thought made sense.
  • I haven't looked at the climate biomes as these will change depending on what changes you incorporate from my ocean map.

It was pretty good. You had most of the correct features.

Just a heads up. Currents don't generally just separate at 90 degrees for no reason. It has to have some sort of hydrodynamic flow or bathymetry feature driving the splitting and merging of currents.

I noticed a couple of your currents where going through the archipelagos instead of along the side of them. While currents can traverse across them, the shallower bathymetry acts as more of a barrier to faster established currents.

I didn't think your long east to southwest warm current in the southern hemisphere were so connected. That's a long way for a warm current to travel through many interfering islands. Warm currents are normally slower and more likely to spread out when it hits a barrier.

I also added a couple smaller counter currents.

Just a note. I recall that circumpolar currents (polar currents that flow 360 degrees without land interference like you have in the south), allow for the currents to be colder and more established (with less mixing). Your northern "arctic" current is going to be warmer than your southern current as it will have more chance of mixing with the warmer currents around it. The land on either side sort of acts like a giant mixing bowl. This will impact on your climate zones along the coastal regions in the north (it also impacts on the development of the hadley/ferrel/polar cell atmospheric circulation system, if you want to go really in depth). Something to take into consideration.

edited map

  • yellow are my warm current edits and green are the cold current edits.
  • those with green or yellow crosses are more cooler/warmer currents respectively.
  • black cross is a current I didn't think belonged there but if there is some bathymetry feature i'm not aware of...
  • $\begingroup$ Thanks a lot. I'll discuss with my friend and we'll update the post with changes $\endgroup$
    – NukeyFox
    Feb 28, 2020 at 18:47

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