<p>My best estimate on what would happen is the following: <br>
 - At the <a href="http://en.wikipedia.org/wiki/Terminator_(solar)" rel="nofollow">twilight zone</a> there would be tremendously fierce and constant windstorms as the heavier cold air rushed from the dark side to displace the lighter air warmed by the Sun. <br>
 - Additionally, the wind patterns would generally align themselves towards and away from the twilight zone. <br>
 - Over a millennia, the storms would probably carve canyons and deep scars into the face of the planet along the twilight zone.<br>
 - Relative calm would be found in the area closest to the Sun as well as farthest from the Sun. <br>
 - If the planet were inhabited, the inhabitant would probably be locked to either the light side or the dark side unless they had some method of navigating through or around the storms.<br>
 - I don't know if it would rain or not, but if it did, it would definitely only rain on the side facing the Sun, as the other side would be perpetually frozen.</p>

<p>I'm not a meteorologist, this is just a thought exercise, so I don't know how accurate any of this is (although I do have some basic knowledge of meteorology).</p>

<p><strong>EDIT</strong>: I found <a href="http://en.wikipedia.org/wiki/Habitability_of_red_dwarf_systems#Tidal_effects" rel="nofollow">this wikipedia article</a>, which seems to support my theories.</p>

<blockquote>
  <p>Due to differential heating, it was argued, a tidally locked planet would experience fierce winds blowing continually towards the night side[citation needed] with permanent torrential rain at the point directly facing the local star, the subsolar point. In the opinion of one author this makes complex life improbable. Plant life would have to adapt to the constant gale, for example by anchoring securely into the soil and sprouting long flexible leaves that do not snap. Animals would rely on infrared vision, as signaling by calls or scents would be difficult over the din of the planet-wide gale. Underwater life would, however, be protected from fierce winds and flares, and vast blooms of black photosynthetic plankton and algae could support the sea life.</p>
</blockquote>

CC BY-SA 3.0
2015-03-29T00:26:44.573Z
Yeah, that would make sense to me, although the article (cited above) states it would constantly rain.  Not sure how or why that might happen.
Ethan Strider
CC BY-SA 3.0
2015-03-29T02:13:17.110Z
Welcome to Earth Science S.E.! Excellent first answer!
L.B.
CC BY-SA 3.0
2015-03-29T04:32:46.903Z
Have a look at the answers to similar question on a sister site: (http://worldbuilding.stackexchange.com/questions/4850/how-would-winds-behave-on-a-tidally-locked-planet),  (http://worldbuilding.stackexchange.com/questions/358/how-extensive-could-a-habitable-twilight-zone-be-on-a-tidally-locked-planet)
Fred
CC BY-SA 3.0
2015-03-29T11:28:15.870Z
Also the answers to this question: [link] (http://worldbuilding.stackexchange.com/questions/10581/effects-of-a-non-rotating-earth)
Fred
CC BY-SA 3.0
2015-04-03T05:48:49.657Z
Thank you for an interesting answer! It however seems to me that you are answering a question: "what would be typical weather patterns (the climate) in various parts of the planet. In this question, I am particularly interested in *how would the weather change*. (I.e. would there be daily/weekly/monthly changes without external forcing, or would it be rainy/windy/sunny almost all the over one particular spot without changes? Sorry if I didn't formulate my question properly.
Irigi
CC BY-SA 3.0
2015-03-29T00:16:58.497Z
2015-03-29T00:22:56.403Z
2015-03-29T00:22:56.403Z
Ethan Strider
<p>On Earth, weather is very much affected by the Earth's rotation around its axis and around the Sun. Even locations that are almost on the equator do have <a href="https://weatherspark.com/averages/29126/Sao-Tome-Sao-Tome-Sao-Tome-and-Principe" rel="noreferrer">strong annual variations</a> in precipitation and other characteristics. On the other hand, on a tidally-locked planet (TLP), there are no cycles. The star is still on one place on the sky. From the point of view of the global circulation models, which are most often used for studies of the climate of TLP, this is an ideal steady state.</p>

<p>My question is: <em>What weather changes and cycles should one expect on tidally-locked planets, where no astronomical cycle acts as external forcing? Would the weather in a particular location change at all?</em></p>

<meteorology><planetary-science><hypothetical>
How would weather change on a tidally-locked terrestrial planet?
Irigi
# How would weather change on a tidally-locked terrestrial planet?

(Asked by: username_0 on 2015-03-22)

On Earth, weather is very much affected by the Earth's rotation around its axis and around the Sun. Even locations that are almost on the equator do have [strong annual variations](https://weatherspark.com/averages/29126/Sao-Tome-Sao-Tome-Sao-Tome-and-Principe) in precipitation and other characteristics. On the other hand, on a tidally-locked planet (TLP), there are no cycles. The star is still on one place on the sky. From the point of view of the global circulation models, which are most often used for studies of the climate of TLP, this is an ideal steady state.

My question is: *What weather changes and cycles should one expect on tidally-locked planets, where no astronomical cycle acts as external forcing? Would the weather in a particular location change at all?*

**Tags:** meteorology, planetary-science, hypothetical


---

## 1 answers

### Answer by username_1 on 2015-03-29. Score: 3

My best estimate on what would happen is the following:   
- At the [twilight zone](http://en.wikipedia.org/wiki/Terminator_(solar)) there would be tremendously fierce and constant windstorms as the heavier cold air rushed from the dark side to displace the lighter air warmed by the Sun.   
- Additionally, the wind patterns would generally align themselves towards and away from the twilight zone.   
- Over a millennia, the storms would probably carve canyons and deep scars into the face of the planet along the twilight zone.  
- Relative calm would be found in the area closest to the Sun as well as farthest from the Sun.   
- If the planet were inhabited, the inhabitant would probably be locked to either the light side or the dark side unless they had some method of navigating through or around the storms.  
- I don't know if it would rain or not, but if it did, it would definitely only rain on the side facing the Sun, as the other side would be perpetually frozen.

I'm not a meteorologist, this is just a thought exercise, so I don't know how accurate any of this is (although I do have some basic knowledge of meteorology).

**EDIT**: I found [this wikipedia article](http://en.wikipedia.org/wiki/Habitability_of_red_dwarf_systems#Tidal_effects), which seems to support my theories.

> Due to differential heating, it was argued, a tidally locked planet would experience fierce winds blowing continually towards the night side[citation needed] with permanent torrential rain at the point directly facing the local star, the subsolar point. In the opinion of one author this makes complex life improbable. Plant life would have to adapt to the constant gale, for example by anchoring securely into the soil and sprouting long flexible leaves that do not snap. Animals would rely on infrared vision, as signaling by calls or scents would be difficult over the din of the planet-wide gale. Underwater life would, however, be protected from fierce winds and flares, and vast blooms of black photosynthetic plankton and algae could support the sea life.

> **Comments:**
> **username_1**: Yeah, that would make sense to me, although the article (cited above) states it would constantly rain.  Not sure how or why that might happen.  
> **username_2**: Welcome to Earth Science S.E.! Excellent first answer!  
> **username_3**: Have a look at the answers to similar question on a sister site: (http://worldbuilding.stackexchange.com/questions/4850/how-would-winds-behave-on-a-tidally-locked-planet),  (http://worldbuilding.stackexchange.com/questions/358/how-extensive-could-a-habitable-twilight-zone-be-on-a-tidally-locked-planet)  
> **username_3**: Also the answers to this question: [link] (http://worldbuilding.stackexchange.com/questions/10581/effects-of-a-non-rotating-earth)  
> **username_0**: Thank you for an interesting answer! It however seems to me that you are answering a question: "what would be typical weather patterns (the climate) in various parts of the planet. In this question, I am particularly interested in *how would the weather change*. (I.e. would there be daily/weekly/monthly changes without external forcing, or would it be rainy/windy/sunny almost all the over one particular spot without changes? Sorry if I didn't formulate my question properly.  

---

