I'm making a mostly water planet with just a few islands and no axil tilt. Basically I'm wondering if my guesses are right, would my equator have lots of storms and hot rain due to the large amount of evaporation. And would my temperate zone also have storms cause of the mass temperature differences between the south and north of it. Or at least make a large air cell or winds. Hopefully this helps but I was planning on having it being slightly smaller then venus (idk like 7500 miles diameters and 3750 miles radius), it orbiting a k star (about same distance as earth would be to its star), having a slightly denser atmosphere with higher oxygen, 6 plates (ones on the poles and four in the middle), and maybe slightly higher calcium in the water. I'm kina new to this planet stuff so sorry if I don't have the best info to guess off of. I'll try to add more info about the planet as I figure more stuff out.
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$\begingroup$ What you're describing is very similar to the conditions on Jupiter, so you might want to look at studies of Jupiter's weather for some clues. Without landfall or seasons, there is nothing to make big storms ever go away. $\endgroup$Robert Rapplean– Robert Rapplean2026-03-31 17:45:02 +00:00Commented 11 hours ago
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$\begingroup$ hadley cell size is mostly caused by rotational speed not temprature. $\endgroup$John– John2026-03-31 20:09:39 +00:00Commented 9 hours ago
1 Answer
Climate is easily the most complicated topic we address
With the little information you've given us, the best answer we can give you is maybe.
A fraction of the variables that must be addressed when discussing the scientific veracity of storms include:
- Specific percentage of exposed land vs. water
- Average depth of the water
- Percentage of water at maximum depth
- Percentage of water at coastal (shallow) depths
- Ambient solar energy
- Stellar temperature
- Radius of planet
- Density of atmosphere
- Composition of atmosphere
- Mass of planet
- Salinity of water (specifically)
- Average chemical composition of water (generally)
- Currents (undersea topology!)
- Wind (land topology!)
- Atmospheric cells
- Chemistry of the crust
- Obliquity (you've answered that, axial tilt = 0)
- Precession (axial wobble)
- Eccentricity (orbital shape)
And without a full topological map of the world, we're basically hamstrung.
And even if we had all that and a lot more... we'd only be able to give you a best guess. Keep in mind humanity still has trouble predicting the weather tomorrow for a planet we've known about for a long honking time. What will happen on an alien planet is never more than a guess.
But, what guesses can we make right now?
Let's assume that the atmosphere, chemical makeup of the crust, sun, and basic nature of the planet are identical to Earth save that yours is a water world with a few islands. We'll also assume that the undersea topology is as varied as Earth's, other than the oceanic average depths will be greater.
Our initial assumption is that storms will be identical to Earth other than Hurricanes/typhoons rarely gain strength to what we call Category 5, which is frequently due to the storm passing onto shallower coastal waters or shelves.
Our next assumption is that there's pretty much always something happening somewhere. This is true on Earth today and will be true on your own world. Consequently, the "number of storms" won't particularly change much, but where they happen will. Rain falls almost everywhere (ignoring high mountain altitudes) but it's moved around by continental conditions (resulting, e.g., in deserts, basically massive rain shadows).
You'll have simpler currents on your world because there's no exposed land to move them around. But you'll still have them, and some of them could be very strong. Those will affect navigation (I'm making an assumption, there) more than storms will. But it also means the storms are more likely to follow (give or take) the track of the currents. There's a strong relationship between currents and wind — and the relationship works in both directions. But it's not an overriding relationship. Storms will generally track currents, but that doesn't mean they must (and I might be overstating the correlation).
Next, we ask Google "do ocean storms form more frequently at the equator?" What we learn is the answer is "no." Evaporation occurs most strongly at the equator, but it takes wind to whip up a storm.
Given that sea surface temperatures need to be at least 80°F (27°C) for tropical cyclones to form, it is unsurprising that they form near the equator. However, with only the rarest exceptions, these storms do not form within 5° latitude of the equator. This is due to the lack of sufficient Coriolis force, the force that causes the cyclone to spin. (Source)
What this suggests is that you could have an increase in storms between the equator and the tropics of Cancer and Capricorn on your world.
Conclusion
So, using limited information, a rough guess is that you'll see more storms of lower strength. They'll form as they do here on Earth, which means not particularly at the equator itself. Your world would be, therefore, easier to navigate — but a lot less comfortable to navigate in.
A Brief Note...
When building worlds, use science as a guide, but never assume science can do the worldbuilding for you. Humanity knows a whole lot less than most people think. Blame it on easy communication and the tendency for graduate students to post information constantly to bolster their careers (I do...). Anyway, the simple truth is that science cannot and will not answer everything. It's a great place to start, but in the end, you as the worldbuilder must choose what you want your world to be.
The field of climatology is so whomping broad that only a handful of people on Earth could say that a decision you made was wrong — and it's not unrealistic that they're wrong to say so. We have, after all, only one data point to work with when it comes to habitable worlds: Earth. And that's it.
