What is the approximate length of a Martian day, from one sunrise to the next?

A Martian day lasts approximately 24 hours and 39 minutes from one sunrise to the next.

Scientists call this solar day a sol. More precisely, a mean Martian solar day is about 24 hours, 39 minutes, and 35 seconds, making it roughly 39 minutes longer than an average Earth day.

The difference matters operationally. Mars mission teams often schedule activities in sols rather than Earth days, and staff working on rover missions may temporarily shift their daily routines to match local daylight. Solar-powered spacecraft particularly depend on the timing of sunrise, sunset, and available energy.

A sol is not exactly the same length every day because Mars’s orbital motion and axial tilt affect apparent solar timing. The term should also be distinguished from Mars’s sidereal rotation period, which measures rotation relative to distant stars rather than the Sun.