Mars' rotation is very similar to Earths, taking 24.6 hours to rotate. It is presently tilted 25 deg, which cause seasons on Mars. Mars is considerably closer to the Sun when the Southern Hemisphere experiences Summer, as a result, dust storms tend to start around this time. Its axis tilt varies from zero to 60 degrees over geological timescales, in part due to the lack of a stabilizing large moon. This causes the amount of Carbon Dioxide to change, so that liquid water is more abundant during some periods.