World Building details

[Glade Riven]

Perhaps there is a difference between False Summer and True Summer?False Summer is wet, rainy, and never gets above about 55 degrees F. True Summer is warmer, drier, sunnier, and a proper contenental summer. Maybe False Summer is shorter, followed by a longer second winter (Deep Winter?) before second spring rolls around and leads into True Summer.

 

[Systole]

If it's flat, presumably like a pancake or wide sheet of "ground," but it's in a universe where orbits actually happen more or less as they do in ours, then clearly it's an artificial construct. No natural object the size of a planet can form a flat shape, gravity causes them to collapse into a sphere. Assuming this is the case, then you already have a major deus ex machina in your world's backstory, and can explain the seasons however you like- perhaps elemental gates open up at different times of the year, and the predominant magical energy from the gates causes the seasons.

If your world somehow is not a created thing, with that flat shape, then clearly the laws of physics are very different in your world's universe, and that means orbits and celestial mechanics work differently. Which, again, gives you an out for explaining any apparent anomalies.

Knowing why the world is flat (and precisely how it's shaped) might help us come up with a reason to explain the seasons, in other words.

Actually, you can make a naturally flat world "where orbits actually happen more or less as they do in ours." Emphasis on "more or less."

In the real world, gravity is spherically symmetric, and diminishes as the square of the distance. However, one can imagine a universe where the gravitational constants are different in the x, y, and z directions. In the case where the constants for x and y are much smaller than z, a planet would naturally assume a disc shape with only a slight curvature across the face.

In this case, the sun would also be disc-shaped, so if the sun was revolving around the planet and rotating on one its long axes, the amount of light the planet saw would vary (i.e. whether it seeing the edge or the face of the sun). Additionally, it would also cause some super-strange seasons if the sun's orbit was precessing around the planet -- the sun would orbit much closer when it was directly overhead. If it was orbiting the edge, where the gravitational constant was weaker, it would orbit farther out.

 

[axp_dave]

Why do you need a reason? Are the PC's in contact with astronomers, sages, or geologists? Make it an unknown to most people or even the experts and it is simply their reality.

Dave

 

[ghostcat]

Lets see what we have is a, presumably circular, disk which the sun rotates round.

1. The sun rotates in a perfect circle over the centre of the disc.

2. The disc rotates under the sun's path.

Assuming that one year equals a full rotation of the disc. This means that any given point will be directly under the sun twice per year. Likewise it will also be at 90 degrees to the sun's path twice per year.

QED,