Equinoxes and Solstices: Dates, Times and What They Mean

Solstices and equinoxes are four exact moments each year, fixed by the tilt of Earth’s axis (about 23.44°) and its position in orbit. At the June and December solstices the Sun reaches its farthest point north or south in the sky; at the March and September equinoxes it crosses the celestial equator. Each falls within a day or so of the same calendar date every year: around 20 March, 21 June, 22–23 September and 21–22 December.

What each one is

Earth’s axis is tilted about 23.44° relative to the plane of its orbit, and it keeps pointing the same way in space as Earth goes around the Sun. For part of the year the Northern Hemisphere leans towards the Sun; six months later the Southern Hemisphere does.

Event	Sun’s position	Northern Hemisphere	Southern Hemisphere
March equinox	Crosses the celestial equator heading north	Start of astronomical spring	Start of astronomical autumn
June solstice	Farthest north, overhead at the Tropic of Cancer	Longest day	Shortest day
September equinox	Crosses the celestial equator heading south	Start of astronomical autumn	Start of astronomical spring
December solstice	Farthest south, overhead at the Tropic of Capricorn	Shortest day	Longest day

Because the hemispheres are reversed, names like “spring equinox” and “winter solstice” are ambiguous. Astronomers use the month names instead.

On the equinoxes the Sun rises close to due east and sets close to due west everywhere outside the polar regions. At the solstices the sunrise and sunset points reach their farthest north or south, and for a few days they barely move, which is where the word comes from: solstice is Latin for “sun standing still”.

Seasons are not caused by distance from the Sun. Earth is actually closest to the Sun in early January, in the middle of the northern winter.

Equinox and solstice times, 2025–2030

All times are UTC, rounded to the minute, computed with Jean Meeus’s algorithms.

Year	March equinox	June solstice	September equinox	December solstice
2025	20 Mar, 09:02	21 Jun, 02:42	22 Sep, 18:20	21 Dec, 15:03
2026	20 Mar, 14:46	21 Jun, 08:25	23 Sep, 00:06	21 Dec, 20:50
2027	20 Mar, 20:25	21 Jun, 14:11	23 Sep, 06:01	22 Dec, 02:42
2028	20 Mar, 02:17	20 Jun, 20:02	22 Sep, 11:45	21 Dec, 08:20
2029	20 Mar, 08:02	21 Jun, 01:48	22 Sep, 17:38	21 Dec, 14:14
2030	20 Mar, 13:52	21 Jun, 07:31	22 Sep, 23:27	21 Dec, 20:10

The local date depends on your time zone. The March 2028 equinox, at 02:17 UTC on 20 March, happens at 22:17 on 19 March in New York. The December 2026 solstice, at 20:50 UTC on 21 December, falls at 05:50 on 22 December in Tokyo. Use the time zone converter for any other place, or see the event marked on the December 2026 calendar.

Why the dates shift

Look down any column of the table and the time moves about six hours later each year, then jumps back in 2028. The reason is the mismatch between the calendar year and the tropical year (equinox to equinox), which averages about 365.2422 days.

A common year of 365 days is roughly a quarter of a day short, so each event arrives about 6 hours later in the following year.
After three such steps, the leap day pulls everything back by a full day. In the table, 2028 is a leap year, and its events are earlier than 2027’s by roughly 18 hours.
The Gregorian rule of skipping leap years in most century years (1900, 2100) corrects the remaining small surplus over the long run. See how leap years work for the arithmetic.

The result is a sawtooth pattern within a narrow window. In UTC the March equinox in this century falls on 19, 20 or 21 March, mostly 20 March; the other events have similar ranges. The 2025–2030 values above all sit on the “usual” dates; local-time dates are what push them to the edges.

Myth 1: day and night are equal on the equinox

The word equinox means “equal night”, but day is longer than night on the equinox almost everywhere. Two definitions are responsible:

Sunrise and sunset are measured from the Sun’s upper edge, not its centre. The Sun’s disc is about half a degree across, so its top clears the horizon before the centre does.
Atmospheric refraction lifts the image of the Sun by about 34 arcminutes near the horizon, so you see it before it is geometrically up.

Together these put sunrise and sunset at the moment the Sun’s centre is about 0.83° below the horizon. That adds several minutes of daylight at each end. On the March 2026 equinox, London had about 12 hours 8 minutes between sunrise and sunset.

The day on which sunrise and sunset are closest to 12 hours apart is sometimes called the equilux. In mid-northern latitudes it comes a few days before the March equinox and a few days after the September one. Calculated for 2026–27:

Place	Spring equilux (approx.)	Autumn equilux (approx.)
London	17–18 March	26 September
New York	17 March	25–26 September
Sydney	25 March	18 September

In Sydney the order is reversed relative to the calendar because March is autumn there.

Myth 2: the seasons start on the equinox or solstice

That is one definition: the astronomical seasons. Meteorologists and climatologists use a simpler one, the meteorological seasons, which group whole calendar months by temperature. This makes monthly statistics easy to compare from year to year.

Northern Hemisphere	Meteorological season	Astronomical season
Spring	1 March – 31 May	March equinox – June solstice
Summer	1 June – 31 August	June solstice – September equinox
Autumn	1 September – 30 November	September equinox – December solstice
Winter	1 December – 28/29 February	December solstice – March equinox

In the Southern Hemisphere swap the labels: meteorological summer is December to February.

Neither is “correct”. Weather services and many official climate records use the meteorological dates; calendars and almanacs tend to use the astronomical ones.

Myth 3: the earliest sunset is on the shortest day

The December solstice is the shortest day in the Northern Hemisphere, but it is not the day of the earliest sunset or the latest sunrise. The cause is the equation of time: solar noon, the moment the Sun is highest, drifts against clock time over the year. Around the December solstice, solar noon moves later by about half a minute per day. Day length is barely changing then, so the whole block of daylight slides later: sunsets bottom out before the solstice and sunrises keep getting later after it.

Calculated for winter 2026–27 (local time, rounded to the minute):

	London	New York
Earliest sunset	about 15:52, mid-December (around 13 Dec)	about 16:29, early December (around 8 Dec)
Solstice, 21 Dec	sunrise 08:05, sunset 15:54	sunrise 07:17, sunset 16:32
Latest sunrise	about 08:07, around 30 Dec	about 07:21, early January (around 4 Jan)

Because the changes are seconds per day near the turning points, the extremes are shallow and several neighbouring days share the same minute. The offset from the solstice is larger closer to the equator, where day length changes more slowly. The same pattern runs in reverse in the Southern Hemisphere in June.

For exact daily times in your own city, see the sunrise and sunset pages or a city page such as London sun times.

Quick reference

Solstices and equinoxes are instants, not days; the date depends on your time zone.
Dates drift by about 6 hours a year and reset with each leap day.
On the equinox, daylight is a few minutes longer than 12 hours.
Astronomical seasons start at solstices and equinoxes; meteorological seasons start on 1 March, 1 June, 1 September and 1 December.
Earliest sunset comes before the December solstice, latest sunrise after it.