First, for scale, this map is about the size of the continental US. Assume that the mountains are about the size of the Rockies. These mountains are jagged on the outer edge, and more sloping on the inside. Everything North of the map is rocky wasteland, and there is an ocean to the south and west. To the east (about the distance from the mainland to the large island) is an unexplored continent. There is constant spring/summertime weather. In this case, the sun rises in the west and sets in the east.

For all intents and purposes, this map has replaced the US, Canada is a rocky wasteland, and Mexico has sunk into the sea.

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    $\begingroup$ This isn't so much weather patterns as it is a general trend, but if this is on the inside of a hollow planet, with a sun in the middle, then it would be warmer near the poles and colder around the equator. This is because as it's spinning, the sides are going to bulge out, (just like the earth) and be further away from the sun than the poles would be. $\endgroup$ Jan 14, 2016 at 23:38
  • $\begingroup$ It's a sphere, because it was created by magic, but I'll probably remove the hollow planet stuff. $\endgroup$ Jan 14, 2016 at 23:44
  • $\begingroup$ "Continental US" includes Alaska, does it? But even then, a Continent of that size will not have constant summer/springtime. Even a planet with no axial tilt would get colder when you approach its poles. So... it could help if you tell us where the Equator might be at this map (if its there at all), how big that world is in general and if that planet does have an axial tilt (if yes, how big). Than it might be possible to forecast your weather and climate. Btw, this world looks generated... it's mountain-ranges look unnatural, somehow.:/ $\endgroup$ Jan 15, 2016 at 7:32
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    $\begingroup$ They look unnatural because they're not in lines - mountains form when plates/land masses collide, which results in a linear range. This looks like what you get when you scrunch up a piece of paper and then lay it out flat again. Which, hey, if this is a magically created world, could provide interestingly plausible geological evidence for some past magical cataclysm. $\endgroup$ Jan 15, 2016 at 11:45
  • $\begingroup$ @Confused Merlin It does not include Alaska, I'm not talking about length, I'm talking about their size. As in, how tall, and things like that. $\endgroup$ Jan 15, 2016 at 14:10

3 Answers 3


Assuming a world similar to Earth (same size, rotation, seasons...) you would have rather similar weather pattern. The one thing that would really change things is if the current are different (and given the different geography, they would).
Western Europe has about the same latitude as New York, and yet it is much warmer due to the Gulf Stream. How you position your currents will have a huge influence.

Otherwise I'd say, due to the planet rotation and the lack of any mountains, the western territories would be really wet, and tropical in the south. A strong monsoon could be expected.

The south and south-east would probably have a Florida/Caribbean climate, while the east would be similar to the eastern coast of the US or north-western Europe depending on the current temperature.

The north would be similar to Canada's climate.

The center is harder to tell, because while the enclosing mountains on each should make it really dry if not a dessert in the south, the more northern parts have huge lakes. Still I would expect a strong continental climate with huge swings in temperature between summer and winter.

One last thing to consider is that given this world seems to have a higher proportion of water than Earth, more water would probably be in the atmosphere. Given that water is a greenhouse gas, global temperatures would be higher with smaller icecaps.

All of this is of course best guesses.

  • $\begingroup$ This answer looks great for your first foray into Worldbuilding SE! The only critique I have (and it's a pretty minor one), is that comparing anything to "Canada's climate" doesn't really help explain anything, because (as opposed to the perennially "cold and snowy" stereotype) Canada is huge, has maritime, coastal, Arctic, prairie, mountain, and pretty much every other kind of climate. Again, consider this a minor critique, overshadowed a warm welcome. $\endgroup$ Jan 16, 2016 at 12:11
  • $\begingroup$ @Leherenn I your answer, it gives a reasonably detailed description, while also stating that there are several variables that could change it. $\endgroup$ Jan 16, 2016 at 17:18
  • $\begingroup$ type_outcast: You're right that a Canadian climate doesn't mean much, but I left it at that for two reasons: one is that I don't know much about it, especially in term of precipitations, second is that the north of the map actually looks pretty much like Canada so you can map it more or less one for one. Islands in the north-north-east, check, prairie in the north, check, mountains in the west and east, check again, only outer the north-west is really different. Thanks for the comment. $\endgroup$
    – Leherenn
    Jan 16, 2016 at 22:01

You're looking at standard weather patterns unless there's something special going on. You can match places to equivalent geography on Earth for your weather. Remembering things like the fact it's going to be wetter on the seaward side of hills/mountains and drier behind them. Temperate island climates are much more moderate than equivalent continental climates.

I can't see anything on that map that would make the weather anything unusual by our world standards.

  • $\begingroup$ Not enough for a full answer, but this would help with finding what weather patterns might be like: earth.nullschool.net. Plus it's really cool looking. $\endgroup$
    – AndyD273
    Jan 15, 2016 at 16:20
  • $\begingroup$ That's pretty helpful $\endgroup$ Jan 15, 2016 at 17:44

Since this continental sized, all in one hemisphere, and with mountains in the center, this is relatively easy to answer. The continent is best divided into quadrants:

North Quadrant

Since you say Canada is a rocky wasteland, I would assume that it has sizable land mass. If it has a sizable land mass, then cold polar fronts will develop over it, as they do over Canada in our world. That would make the northern quadrant of this region dominated by cold polar fronts, just as the northern parts of the US are. Parts of the north relatively far from water, will have continental climates, like Minneapolis or Omaha. Parts closer to the water will have more moderate winters, like Detoit of Chicago. Parts directly bordering and to the south of bodies of water will have the cool summers and heavy snowfall of Cleveland or Buffalo.

However, the mountains at center will prevent summer thuderstorms from getting that far north. The entire north will be dryer than our US; instead of a rainy summer corn belt, you will have a dry steppe as in Central Asia, more suitable for wheat or grazing.

East Quadrant.

Just like in the United states, you could expect a warm 'Gulf Stream' to form in the southern sea and prevented from moving west by the pictured 'southern hook' peninsula. This warm current will bring more moderate winters (compared to the north) up the entire East coast. However, the mountains being higher than the Appalachians will provide a difference from out United States, and will help to further prevent cold winters.

The southern part of the East coast will probably not freeze in the winter, making it like Florida. The northern part will freeze occasionally, but not be as cold or snowy in the winter as the Northeast US.

Rainfall would be expected to be the same, that is, the same year-round and heavy.

South Quadrant

The big difference here is that the central mountains protect the south from cold winters, and also trap rain moving north from the southern sea. Expect the central mountains to have a cold continental climate with heavy summer rains. The coast will be hot and wet in the summer, like our gulf coast, but won't freeze in the winter. Without freezing, and with lots of rain and rivers flowing down from the mountains, expect sub-tropical forests to cover the coast, like southern China.

West Quadrant

Benefiting from lots of islands and oceanic exposure, the climates here will also be very moderate. The southern parts (including the large, far island) will have a Mediterranean climate like California (or, you know, the Mediterranean); the northern parts a cool oceanic climate like Northern Europe. The northern parts directly facing the ocean will get heavier rains and see thick forests, as in the Olympic peninsula and Galicia, Spain, but inland the rain will trail off. However, the region will be cool enough that there will be enough waters for tree cover and you will get fields and forests like northern France.


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