It s Raining on Titan . ... In fact, it's likely been raining methane on Titan and that's not an April Fools' joke . ... That scenario is consistent with seasonal rain storms temporarily darkening Titan's surface along the moon's equatorial regions, as seen by instruments onboard the Cassini spacecraft . Of course on frigid Titan , with surface temperatures of about -290 degrees F (-180 degrees C), the cycle of evaporation, cloud formation, and rain involves liquid methane instead of water. ...