Seasons on Mars

Mars experiences solstices and equinoxes just like Earth. They're associated with seasons on the red planet, just like they are on Earth. However, Martian seasons aren't anything like Earth's. The atmosphere on Mars is very thin and contains a different blend of gases. Mars also has a more elliptical orbit causing the planet's distance from the sun to vary much more. These cause temperatures to rise and fall through a bigger range of temperatures than on Earth. However, most of Mars stays far colder than most of Earth.

On Mars, the northern hemisphere spring lasts seven Earth months. Summer lasts six months, fall lasts five months, and winter lasts four months. The seasons vary in length so much because the planet is in the slowest part of its orbit in the spring and summer and the fastest in the fall and winter. The opposite is true for the seasons in the southern hemisphere where winter is longer than summer.

For centuries, astronomers have watched the polar ice caps on Mars grow and shrink. As the pole that has been tilted away from the sun returns to sunlight, a large white area appears. It shrinks and disappears as that pole continues to tip toward the sun. The Martian polar ice caps aren't made of water ice like Earth's. They are frozen carbon dioxide. Most of the planet's atmosphere is carbon dioxide and the poles take turns getting cold enough to freeze the gas out of the air. So much of the gas freezes and thaws over the course of a Martian year, spacecraft that have visited the planet have measured a 25% thinning of the air when the ice caps are largest.

Here are when the equinoxes and solstices on Mars occur during the 2010 decade.

Northward equinox Northern solstice Southward equinox Southern solstice
May 13, 2010 at 04:51 November 12, 2010 at 17:19 April 8, 2011 at 09:41
September 13, 2011 at 14:25 March 30, 2012 at 04:20 September 29, 2012 at 16:06 February 23, 2013 at 08:28
July 13, 2013 at 14:25 February 15, 2014 at 03:48 August 17, 2014 at 16:18 January 11, 2015 at 07:33
June 18, 2015 at 12:33 January 13, 2016 at 02:38 July 4, 2016 at 15:53 November 28, 2016 at 07:46
May 5, 2017 at 11:45 November 20, 2017 at 01:43 May 22, 2018 at 14:43 October 16, 2018 at 07:22
March 23, 2019 at 11:33 October 8, 2019 at 00:59