Titan

Science Daily: Intense storms batter Saturn’s largest moon, scientists report - Extreme methane rainstorms appear to have a key role in shaping Titan’s icy surface

summary - Titan, the largest of Saturn's more than 60 moons, has surprisingly intense rainstorms, according to research by a team of UCLA planetary scientists and geologists. Although the storms are relatively rare -- they occur less than once per Titan year, which is 29 and a half Earth years -- they occur much more frequently than the scientists expected.