Seasons on Earth

At the March equinox, the sun crosses the equator going north. It's often called the start of spring in the northern hemisphere and the start of autumn or fall in the southern hemisphere. In most of the northern hemisphere, sunrise and sunset happen exactly 12 hours apart just a few days before the March equinox. Likewise, they happen exactly 12 hours apart just a few days later in most of the southern hemisphere. At and close to the poles, the sun travels along the horizon without really rising or setting.

At the June solstice, the sun is as far north as it goes, at 23.4°. It's often called the start of summer in the northern hemisphere and the start of winter in the southern hemisphere, even though many people would feel those seasons are already well underway where they are. In most of the northern hemisphere, the sun is up the longest. Likewise, in most of the southern hemisphere, the sun is up the shortest time. However, at and close to the north pole, the sun never sets. And at and close to the south pole, it never rises.

At the September equinox, the sun crosses the equator going south. People often call it the start of autumn in the northern hemisphere and the start of spring in the southern hemisphere. For most of the southern hemisphere, sunrise and sunset will happen exactly 12 hours apart a few days before the equinox. And for most of the northern hemisphere, they'll happen exactly 12 hours apart a few days later. At and close to the poles, the sun travels along the horizon without really rising or setting.

At the December solstice, the sun is as far south as it goes, at 23.4°. This is often called the start of summer in the southern hemisphere and the start of winter in the northern hemisphere, although those seasons would seem to be well underway at many locations. In most of the southern hemisphere, the days are longest. In most of the northern hemisphere, the days are shortest. At and close to the south pole, the sun never sets. At and close to the north pole, the sun never rises.

Here are the equinox and solstice times for the 2010 decade.

Year March equinox June solstice September equinox December solstice
2010 March 20 at 17:33 June 21 at 11:29 September 23 at 03:09 December 21 at 23:39
2011 March 20 at 23:21 June 21 at 17:17 September 23 at 09:05 December 22 at 05:31
2012 March 20 at 05:15 June 20 at 23:09 September 22 at 14:49 December 21 at 11:12
2013 March 20 at 11:02 June 21 at 05:04 September 22 at 20:45 December 21 at 17:11
2014 March 20 at 16:58 June 21 at 10:52 September 23 at 02:30 December 21 at 23:04
2015 March 20 at 22:46 June 21 at 16:38 September 23 at 08:21 December 22 at 04:48
2016 March 20 at 04:31 June 20 at 22:35 September 22 at 14:22 December 21 at 10:45
2017 March 20 at 10:29 June 21 at 04:25 September 22 at 20:02 December 21 at 16:29
2018 March 20 at 16:16 June 21 at 10:08 September 23 at 01:55 December 21 at 22:23
2019 March 20 at 21:59 June 21 at 15:55 September 23 at 07:51 December 22 at 04:20