<p>So far, we don't have anywhere near enough detail to identify weather on planets in other star systems. We even have difficulty working out the size of some of them, so it may be a while till we can get a good idea as to weather.</p>

<p>So the answer is going to be in our solar system. </p>

<p>As for extremes, we have a couple of options:</p>

<p><strong>WIND</strong></p>

<p>Saturn and Neptune have the highest wind speeds, and as Neptune has the most extreme difference between East-West and West-East winds, I would be tempted to say it has the most extreme weather.</p>

<p><img src="https://i.sstatic.net/SMw3x.png" alt="enter image description here"></p>

<p>Taken from <a href="http://www.springerreference.com/docs/html/chapterdbid/366754.html" rel="noreferrer">http://www.springerreference.com/docs/html/chapterdbid/366754.html</a></p>

<p><strong>TEMPERATURE</strong></p>

<p>Pluto is incredibly cold, but it doesn't vary much, so should we call it an extreme? Mercury has a much more extreme range of temperatures. From sunside (over 400C) to coldside (almost -200C) gives a difference of 600 degrees Celsius!</p>

CC BY-SA 4.0
2021-10-27T17:34:32.107Z
+1 You make a good point about what should be considered extreme weather. "Good weather" implies very specific ranges of temperature, wind speed, pressure, radiation, precipitation, and particulates. Bad weather can be bad along any of those dimensions.
WaterMolecule
CC BY-SA 3.0
2013-09-24T19:52:20.450Z
2013-09-24T19:52:20.450Z
Rory Alsop
<p>Molten Iron and hot sand - <a href="http://www.nasa.gov/jpl/spitzer/brown-dwarf-20140107/" rel="noreferrer">it's not easy to think of something more extreme than this</a>.
Add that to the high gravity of a small, dense Brown Dwarf. Theory predicts they can be as small as 0.75 RJup (if old enough) and much more massive.</p>

<p>I know, BDs are not planets. Howewer at some places, the boundaries are not well defined.
Then, I imagine that a high mass planet close to or even above what the astronomers define as the minimum mass for a BD could have a similar weather. Or could it not?</p>

<p>This mass could be anywhere between 10 and 17 MJ depending on metallicity and other parameters. I saw this numbers in a paper at arxiv.org - sorry for not remembering it's name now. And it seems there are planets heavier than that in the net lists.</p>

<p>Thanks to Jupiter's gravity, Io have a molten core and plenty of volcanoes.
Now, what would be the climate of a planet that is subject to the much stronger pull of a pulsar or even a black hole? or the most extreme 'hot jovians' orbiting around an A/F star in few days (or just hours) and with a temperature above 3000 K...
Or going to another opposite, an ancient rogue world as cold as the circundant space or even colder (if immersed in the 'boomerang' nebula for instance) with enough atmosphere pressure to have pools of liquid Helium.</p>

CC BY-SA 3.0
2014-01-30T13:54:11.887Z
2014-01-30T14:40:56.587Z
2014-01-30T14:40:56.587Z
Bruno Alessi
<p>I would say on the gas giants: Jupiter, Saturn, Uranus and Neptune.</p>

<p>Storms on Jupiter, such as the Great Red Spot or Oval BA, are well known.</p>

<p>Storms on Saturn, such as the Dragon Storm or the Great White Spot, are well known.</p>

<p>Storms on Uranus are not common, but there is one: the Uranus Dark Spot.</p>

<p>Storms on Neptune are very common: the former Great Dark Spot, the former Scooter and much more.</p>

<p>Storms on the inner planets also happen:</p>

<p>Storms on Mars are pretty rare, but one type is not, a dust devil.</p>

<p>Storms on Venus are common, cyclones similar to Earth's storms appear.</p>

<p>Storms on Mercury are extremely rare, mostly due to the lack of an atmosphere.</p>

<p>Storms on Earth, you all know.</p>

CC BY-SA 3.0
2014-03-28T19:41:02.037Z
2014-03-28T19:41:02.037Z
DeathItself
<p>I'd say that <a href="http://en.wikipedia.org/wiki/HD_189733b">HD 189733b</a> is a good candidate for the most extreme <em>known</em> weather on another planet (outside our Solar System).</p>

<p>According to some recent <a href="http://www.space.com/22614-blue-alien-planet-glass-rain.html">news accounts</a>, the atmospheric temperature is believed to be over 1000° C, with 7000 kph winds. (For comparison to the data in Rory Alsop's answer, that's about 1900 meters per second.)</p>

<p>And it rains molten glass. Sideways.</p>

<p><strong>UPDATE :</strong> As Guillochon points out in a comment, <a href="http://en.wikipedia.org/wiki/HD_80606_b">HD 80606 b</a> likely has even higher winds, though they're not continuous. It's a Jovian with an extremely eccentric orbit. Quoting the Wikipedia article:</p>

<blockquote>
  <p>Computer models predict the planet heats up 555 °C (1,000 °F) in just
  a matter of hours triggering "shock wave storms" with winds that move
  faster than the speed of sound, at 3 miles per second.</p>
</blockquote>

<p>which, in civilized units, is about 4800 meters/second. Probably no molten glass rain, though, so it's not clear that it's more "extreme".</p>

CC BY-SA 3.0
2013-11-10T05:30:05.327Z
@Guillochon: I've added your information to my answer.
Keith Thompson
CC BY-SA 3.0
2013-09-24T22:11:15.403Z
Wow - I hadn't thought they had managed to get thermal mapping data for it. This answer definitely wins!
Rory Alsop
CC BY-SA 3.0
2013-09-25T04:11:20.873Z
[HD 80606b](http://en.wikipedia.org/wiki/HD_80606_b) has this one beat, both in the extremes in temperature (800K to 1500K within 6 hours) and in the wind speed (~5,000 m/s).
Guillochon
CC BY-SA 3.0
2013-09-24T20:21:31.950Z
2013-11-10T05:29:52.387Z
2013-11-10T05:29:52.387Z
Keith Thompson
<p>On Venus, there is really inhospitable weather, as well as within the gas giants in our solar system. Are there examples of even more extreme weather on planets found in other solar systems than ours?</p>

CC BY-SA 3.0
2013-09-24T19:49:31.800Z
Meta question on relevancy of planetary science questions: http://meta.astronomy.stackexchange.com/questions/1/where-do-we-draw-the-line-concerning-planetary-science-questions
called2voyage
<exoplanet><weather>
What is the most extreme weather found on another planet?
bogen
# What is the most extreme weather found on another planet?

(Asked by: username_0 on 2013-09-24)

On Venus, there is really inhospitable weather, as well as within the gas giants in our solar system. Are there examples of even more extreme weather on planets found in other solar systems than ours?

**Tags:** exoplanet, weather

> **Comments:**
> **username_1**: Meta question on relevancy of planetary science questions: http://meta.astronomy.stackexchange.com/questions/1/where-do-we-draw-the-line-concerning-planetary-science-questions  

---

## 4 answers

### Answer by username_6 on 2013-09-24. Score: 21 | Accepted answer

I'd say that [HD 189733b](http://en.wikipedia.org/wiki/HD_189733b) is a good candidate for the most extreme *known* weather on another planet (outside our Solar System).

According to some recent [news accounts](http://www.space.com/22614-blue-alien-planet-glass-rain.html), the atmospheric temperature is believed to be over 1000° C, with 7000 kph winds. (For comparison to the data in username_2's answer, that's about 1900 meters per second.)

And it rains molten glass. Sideways.

**UPDATE :** As username_7 points out in a comment, [HD 80606 b](http://en.wikipedia.org/wiki/HD_80606_b) likely has even higher winds, though they're not continuous. It's a Jovian with an extremely eccentric orbit. Quoting the Wikipedia article:

> Computer models predict the planet heats up 555 °C (1,000 °F) in just
> a matter of hours triggering "shock wave storms" with winds that move
> faster than the speed of sound, at 3 miles per second.

which, in civilized units, is about 4800 meters/second. Probably no molten glass rain, though, so it's not clear that it's more "extreme".

> **Comments:**
> **username_2**: Wow - I hadn't thought they had managed to get thermal mapping data for it. This answer definitely wins!  
> **username_7**: [HD 80606b](http://en.wikipedia.org/wiki/HD_80606_b) has this one beat, both in the extremes in temperature (800K to 1500K within 6 hours) and in the wind speed (~5,000 m/s).  
> **username_6**: @username_7: I've added your information to my answer.  

---

### Answer by username_2 on 2013-09-24. Score: 17

So far, we don't have anywhere near enough detail to identify weather on planets in other star systems. We even have difficulty working out the size of some of them, so it may be a while till we can get a good idea as to weather.

So the answer is going to be in our solar system.

As for extremes, we have a couple of options:

**WIND**

Saturn and Neptune have the highest wind speeds, and as Neptune has the most extreme difference between East-West and West-East winds, I would be tempted to say it has the most extreme weather.

![enter image description here](https://i.sstatic.net/SMw3x.png)

Taken from <http://www.springerreference.com/docs/html/chapterdbid/366754.html>

**TEMPERATURE**

Pluto is incredibly cold, but it doesn't vary much, so should we call it an extreme? Mercury has a much more extreme range of temperatures. From sunside (over 400C) to coldside (almost -200C) gives a difference of 600 degrees Celsius!

> **Comments:**
> **username_3**: +1 You make a good point about what should be considered extreme weather. "Good weather" implies very specific ranges of temperature, wind speed, pressure, radiation, precipitation, and particulates. Bad weather can be bad along any of those dimensions.  

---

### Answer by username_4 on 2014-01-30. Score: 5

Molten Iron and hot sand - [it's not easy to think of something more extreme than this](http://www.nasa.gov/jpl/spitzer/brown-dwarf-20140107/).
Add that to the high gravity of a small, dense Brown Dwarf. Theory predicts they can be as small as 0.75 RJup (if old enough) and much more massive.

I know, BDs are not planets. Howewer at some places, the boundaries are not well defined.
Then, I imagine that a high mass planet close to or even above what the astronomers define as the minimum mass for a BD could have a similar weather. Or could it not?

This mass could be anywhere between 10 and 17 MJ depending on metallicity and other parameters. I saw this numbers in a paper at arxiv.org - sorry for not remembering it's name now. And it seems there are planets heavier than that in the net lists.

Thanks to Jupiter's gravity, Io have a molten core and plenty of volcanoes.
Now, what would be the climate of a planet that is subject to the much stronger pull of a pulsar or even a black hole? or the most extreme 'hot jovians' orbiting around an A/F star in few days (or just hours) and with a temperature above 3000 K...
Or going to another opposite, an ancient rogue world as cold as the circundant space or even colder (if immersed in the 'boomerang' nebula for instance) with enough atmosphere pressure to have pools of liquid Helium.


---

### Answer by username_5 on 2014-03-28. Score: 2

I would say on the gas giants: Jupiter, Saturn, Uranus and Neptune.

Storms on Jupiter, such as the Great Red Spot or Oval BA, are well known.

Storms on Saturn, such as the Dragon Storm or the Great White Spot, are well known.

Storms on Uranus are not common, but there is one: the Uranus Dark Spot.

Storms on Neptune are very common: the former Great Dark Spot, the former Scooter and much more.

Storms on the inner planets also happen:

Storms on Mars are pretty rare, but one type is not, a dust devil.

Storms on Venus are common, cyclones similar to Earth's storms appear.

Storms on Mercury are extremely rare, mostly due to the lack of an atmosphere.

Storms on Earth, you all know.


---

