The 'arrow' is bigger than the U.S state of Texas - around 930 miles long - and was was detected on the Saturn moon by Nasa's Cassini spacecraft in September 2010.
The discovery of its origins on Titan, described by researchers as Earth's 'strange sibling', could now be used to better understand weather systems on our own planet, particularly in relation to climate change.
© NASA/JPL/SSIMethane rain: The huge white arrow-shaped cloud on the left of this image of Titan is thought to be caused by atmospheric pressure surges, say scientists
'These atmospheric waves are somewhat like the natural, resonant vibration of a wine glass,' said Jonathan L. Mitchell, UCLA's assistant professor of earth and space sciences and of atmospheric and oceanic sciences.
'Individual clouds might "ring the bell", so to speak, and once the ringing starts, the clouds have to respond to that vibration.'
That response sees the clouds being pushed into various surprising shapes, such as an arrow.
The clouds can cause intense rainfall - sometimes more than 20 times Titan's average for a season - and may be crucial in carving out Titan's surface by erosion, via the formation of rivers and streams.
© PAWater planet: A Nasa artist's impression of a probe from the Cassini spacecraft floating on a lake of Methane on Titan
In the research, published in the online edition of the journal Nature Geoscience, Mitchell and a colleague describe Titan's climate as 'all-tropics', meaning that the entire planet experiences the weather phenomena that on Earth are confined to the equatorial regions.
'Titan's all-tropics climate gives us the opportunity to study tropical weather in a simpler setting than on Earth,' said Mitchell.
'Our hope is that this may help us understand Earth's weather in a changing climate.
'Titan is like Earth's strange sibling - the only other rocky body in the solar system that currently experiences rain.'
Titan has a thick nitrogen atmosphere and experiences rain made of natural methane gas.
That means that there is lots of water on Titan too, but it is all frozen in the crust at very low temperatures.
However, methane is thermodynamically active in the lower atmosphere and, much like water vapor on Earth, forms rain clouds.
Scientists think that Earth, shortly after it formed an atmosphere, had large amounts of methane and very little oxygen.
Methane provided an important greenhouse warming process that probably prevented Earth from remaining in a perpetual ice age, because at the time the Sun was younger and weaker, said Mitchell.
'Therefore, by studying Titan's modern climate, we may gain new insights about the way the early Earth's climate was,' said Mitchell.
How did you guys MISS the city at the south pole?
[Link]Come on; wake up.