Other important gases in the air of Mars are nitrogen and oxygen. There is much less oxygen in the air of Mars than we have on Earth. We would not be able to breathe the air on Mars. Mars has water vapor in the air, but Earth has four times as much. Mars has weather, but it is different than Earth's.
Scientists have pictures of clouds on Mars.
The clouds are made of water vapor. Scientists do not know if it ever rains on Mars. They do know Mars has winds and very big dust storms.