Mars facts · Day and year
How long is a day on Mars?
A day on Mars, called a sol, lasts 24 h 39 min 35 s: about 40 minutes longer than a day on Earth. A year on Mars lasts 687 Earth days, or about 669 sols. Right now it’s day 9 of Mars Year 39.
Updated Sources (6)
How long is a day on Mars?
A day on Mars lasts 24 h 39 min 35 s, on average from one noon to the next. Scientists call it a sol, short for “solar day”, to tell it apart from a day on Earth, which is about 40 minutes shorter.[1][2]
Mission clocks split a sol into 24 Mars hours of 60 minutes and 60 seconds each, so every Mars hour is a little longer than ours. NASA’s Viking landers started that practice in 1976.[1] Our Mars clock shows the time on Mars right now.
How long does Mars take to spin?
Mars turns once against the background stars every 24 hours, 37 minutes and 22.7 seconds. Earth takes 23 hours, 56 minutes and 4 seconds.[1] A sol is about 2 minutes longer than one turn, because Mars also moves along its orbit as it spins: it has to turn a little extra before the Sun is back in the same place in its sky.
How long is a year on Mars?
A year on Mars, from one northern spring to the next, lasts 686.97 Earth days, or 668.6 sols.[1] That is 1.88 times as long as a year on Earth.[3]
Why are Mars’s seasons different lengths?
Mars has seasons for the same reason Earth does: its axis is tilted, by 25.2° against Earth’s 23.4°.[3] But its orbit is more stretched (its eccentricity is 0.0935, against Earth’s 0.0167), so Mars moves faster when it is near the Sun and slower when it is far away.[3] That makes some seasons much longer than others.[2]
| Position around the Sun (Season (Ls)Ls is Mars’s position around the Sun in degrees — 0° starts northern spring, 90° summer, 180° autumn and 270° winter — so it tells you the season.More in the glossary) | North | South | Length |
|---|---|---|---|
| 0° to 90° | Spring | Autumn | About 194 sols |
| 90° to 180° | Summer | Winter | About 178 sols |
| 180° to 270° | Autumn | Spring | About 142 sols |
| 270° to 360° | Winter | Summer | About 154 sols |
Season lengths are NASA’s, in whole sols. Season names follow the northern hemisphere, as scientists do. Right now it’s start of northern spring on Mars.[1][2]
Mars is closest to the Sun at Ls 251°, shortly before northern winter begins. That timing is tied to the global dust storms that sometimes start in that season.[1]
What year is it on Mars?
It’s Mars Year 39. Scientists number Mars years from Mars Year 1, which began on Apr 11, 1955, and each new year starts at the northern spring equinox.[4][5] Mars Year 39 began on Sep 30, 2026, at 08:16 UTC, the European Space Agency says.[5] Today is day 9 of the year.
How do rover teams count sols?
Each mission counts sols from its landing. NASA’s Viking landers, Phoenix, Curiosity, InSight and Perseverance called landing day sol 0; Mars Pathfinder, Spirit and Opportunity called it sol 1.[1] Perseverance is on sol 2,004 and Curiosity on sol 5,039.
Because a sol is about 40 minutes longer than an Earth day, living on Mars time is hard. After Curiosity landed in 2012, its team worked on Mars time for three months, starting work a little later every day, before switching back to regular Earth hours.[6]
Questions
How many hours are in a day on Mars?
24 hours, 39 minutes and 35 seconds, about 40 minutes longer than a day on Earth.
What is a sol?
A day on Mars, from noon to noon on average: 24 h 39 min 35 s. The word is short for “solar day”.
How long does Mars take to rotate?
24 hours, 37 minutes and 23 seconds, measured against the stars. That is about 2 minutes shorter than a sol, because Mars also moves along its orbit as it turns.
How long is a year on Mars?
687 Earth days, or about 1.9 Earth years.
How many days are in a year on Mars?
About 669 sols, the same as 687 Earth days.
What year is it on Mars?
Mars Year 39, which began on Sep 30, 2026. Scientists count from Mars Year 1, which began on Apr 11, 1955.
Why are the seasons on Mars different lengths?
Because Mars’s orbit is more stretched than Earth’s. Mars moves faster when it’s closer to the Sun, so northern autumn lasts about 142 sols while northern spring lasts about 194.
Sources
- NASA GISS — Mars24 Sunclock — Technical Notes on Mars Solar TimePrimary · checked Oct 4, 2026
- NASA Science — Mars: FactsPrimary · checked Oct 4, 2026
- NASA NSSDCA — Mars Fact SheetPrimary · checked Oct 4, 2026
- NASA Planetary Data System — start_mars_year (data dictionary)Primary · checked Oct 4, 2026
- ESA — Happy New Year on MarsPrimary · checked Oct 4, 2026
- NASA JPL — Curiosity Team Switches Back to Earth TimePrimary · checked Oct 4, 2026