How to use the page
The box at the top shows the Next equinox or solstice, its date and time in your time zone, and how many days are left. Under it, two figures show which season it starts in the Northern Hemisphere and the Southern Hemisphere.
The main table lists the four events, the March equinox, June solstice, September equinox and December solstice, for 12 years starting with last year. Each cell gives the instant in UTC, with the same moment in your own time zone underneath. A last table summarizes which season each event begins in each hemisphere. The times are calculated to within a few minutes.
What equinoxes and solstices are
Earth’s axis is tilted by about 23.4 degrees. As Earth orbits the Sun, first one hemisphere and then the other leans toward it. At a solstice, the tilt points most directly toward or away from the Sun: the Sun reaches its highest or lowest noon position of the year, and days are longest in one hemisphere and shortest in the other. At an equinox, the Sun crosses the celestial equator, and day and night are close to equal length everywhere.
| Event | Usual date (UTC) | Northern Hemisphere | Southern Hemisphere |
|---|---|---|---|
| March equinox | 19–21 March | Spring begins | Autumn begins |
| June solstice | 20–21 June | Summer begins | Winter begins |
| September equinox | 22–23 September | Autumn begins | Spring begins |
| December solstice | 21–22 December | Winter begins | Summer begins |
Each event has its own guide: the March equinox, the June solstice, the September equinox and the December solstice.
Astronomical and meteorological seasons
The equinoxes and solstices mark the start of the astronomical seasons. Weather services usually use meteorological seasons instead, which start on the first day of a month: in the Northern Hemisphere, spring from 1 March, summer from 1 June, autumn from 1 September and winter from 1 December. Both are in common use; see meteorological vs astronomical seasons for why the two systems exist.
Why your local date can differ
Because each event is one instant for the whole planet, its local date depends on your time zone. An equinox in the late evening UTC can fall on the next day in Asia and Australia, and one shortly after midnight UTC can fall on the previous day in the Americas. That is why the table shows your own time under each UTC time. For the daylight that results, see sunrise and sunset times.