Lorenz and Lunine, Icarus, 2002, 158, 557
Titan -- Saturn's largest moon --
has an interesting situation too, where the
surface of Titan is right around the triple point
for methane.
Lorenz and Lunine, Icarus, 2002, 158, 557
Above the solid line you can find solid, liquid, and gas; below the solid line only liquid and gas are stable.
The dashed and dotted are two guesses for Titan's atmospheric temperature profile.
Notice the pressure on Titan -- about what it is on Earth (1013 mbar is sea level on Earth)!
The result is that it can snow up high in Titan's atmosphere but not on the ground. The snow turns to liquid on its way down.
Nevertheless, notice that the surface on Titan is pretty close to the triple point for methane. It might methane-snow on tall mountains.