Eternal seasons bind to geographical areas

Question

I created a world a few month ago for a role play game, Ryuutama. The game system is higly based on season and weather, but I'm not good in time gestion as GM. I so decided that regions will have their season, lasting forever.

I was wondering, if this weather setup is possible?

World informations:

• 4 regions: the most South island is the Spring Island. Then you have a bit North the archipelago of Summer, composed of jungle island on the northern and southern edge, and arid islands in the middle. North, you've then the Autumn archipelago, wet and rainy and the most North, you've the Winter island. There's a large volcano on the last island, in an Hawaian like perpetual eruption. The remaining part of the world are oceans. The larger islands (Spring and Winter) have approximatively 200 km of radius, other islands maximum 50 km of radius.

• The planet is Earth-like, with Earth-like wildlife. The planet may be smaller than Earth but with a equivalent gravity. The star of this planet is Sun-like. There may be multiple satellite if its help the weather scenario.

• Humans have an early industrial era activity (steampunk style, with a magical non polluting energy source).

• There is some magic, but not enough to influence weather on a large scale.

Answer 1

Seasons are caused by Earth's tilt. In a planet with (nearly) no inclination, like Venus, there won't be any seasons and weather would change or remain the same according to different phenomena. You can play with latitude and elevation from sea level to make the weather as you like it. Only, in a planet like that, you wouldn't have names for things as "spring" or "winter", since those wouldn't exist.

Answer 2

Skip the latitude changes and go with altitude

The best way to have all these lands, is to have them ringing the equator at different altitudes.

Check out the climate graphs for these three cities in Bolivia: Santa Cruz de la Sierra (400 m); Cochambamba (2500 m); and El Alto (4100 m).

• Santa Cruz de la Sierra's hottest month has a average high/low of 31C/21C (88F/70F); its coldest month is 23C/14C (73F/60F).
• Cochabamba's hottest is 25C/12C (77F/53F) and coldest is 23C/1C (74F/34F).
• El Alto's hottest is 17C/2C (63F/36F) and coldest is 13C/-4C (56F/24F).

Just these cities should give you the range of climates you are looking for. Santa Cruz is in a tropical forest in the Amazon Basin. Cochabamba's nickname is 'the city of eternal spring.' El Alto's coldest months are equivalent to temperate high altitude cities like Denver in March or November; incidentally, these are the snowiest two months in Denver, so El Alto will see snowy winters for sure. El Alto's warmer months is equivalent to Denver's April or October, so while not exactly winter, its not super warm. And you can always put the city a little higher up the mountain to make it even colder. However, you have to think that cities only go where there is agriculture; given that El Alto is the highest major city in the world, and its growing season is pretty short as it is, its hard to see how to put a city even higher up.

Also note, is that Bolivia is not directly on the equator. If it were, the temperatures would be even steadier year-round. A spring city even closer to the equator would be Bogota, Columbia, where the daily mean only varies about 1F from month to month.

How to explain an island with a high altitude plateau.

This one is relatively easy; put all these islands on a rift valley. Ethiopia is one giant volcanic plug that was thrust up out of the lowlands. Look at its map:

This section of highlands is about 500 km east to west, and 1000 km north to south. So it is very possible to have volcanic mountains thrust up out of a shallow sea to make island plateaus at your desired altitude. Currently the plateau is around 2000 m high, perfect for your spring city (Ethiopia's capital Addis Ababa is a good spring city candidate). Thirty million years ago, when the Ethiopian flood basalts were being laid down, the plateau may have been even higher. It isn't to much of a stretch to imagine a 4000m plateau for your winter island.

Answer 3

In theory, a tidally locked planet would have static seasonal bands, but not exactly in the way you want / describe.

You'd have year-round summer at the pole facing the sun, then a sub-tropic, cooler and cooler as you go "south" from the pole facing the sun. Then everything beyond the "equator" would be permanent night time, permanent winter.

You'd have intense, nearly constant storms over the sunward pole if that pole featured a good amount of surface water (which it most likely would) and in the sub-tropical region, as well as along the day-night dividing line (where warmer currents push wet air into the colder region, which immediately would condense and flow back north / sunward.)