It certainly is starting to seem more and more like it was fairly wet some time in the past. Without doubt it had it's share of various storm types as it still does. No idea personally how the smaller gravity would affect their behaviour specifically, tho I do believe atmospheric density is a significant factor.
Originally Posted by Bad Ronald
One major difference is also the lack of strong magnetic field. Am not sure if it is assumed to have deteriorated over time or if it is thought to have been insignificant to begin with. Combined with smaller gravity, the lack of magnetic field is I believe fairly commonly thought to rather adversely affect planetary atmosphere.
Mars has 10% of the Earth's mass & 38% of its gravity yes? This is probably why Mars failed to stay Earthlike or Class M as Star Trek calls it
The dog, the dog, he's at it again!