In 2027 the seasons change on March 20, June 21, September 23 and December 21 in US Eastern Time. Spring begins with the March equinox on Saturday, March 20, at 4:25 p.m. EDT (20:25 GMT). The summer solstice is on Monday, June 21, the fall equinox on Thursday, September 23, and the winter solstice late on Tuesday, December 21, which is already December 22 in the UK.
Equinox and solstice dates and times for 2027
Each of these events is a single moment, the same for the whole planet. The table gives it in US Eastern Time and in UK time. The times are from the U.S. Naval Observatory; an independent calculation by timeanddate gives the same dates and differs by no more than a minute.
| Event | Season that begins (Northern Hemisphere) | US Eastern Time | UK time |
|---|---|---|---|
| March equinox | Spring | Saturday, March 20, 4:25 p.m. EDT | Saturday, March 20, 20:25 GMT |
| June solstice | Summer | Monday, June 21, 10:11 a.m. EDT | Monday, June 21, 15:11 BST |
| September equinox | Fall (autumn) | Thursday, September 23, 2:02 a.m. EDT | Thursday, September 23, 07:02 BST |
| December solstice | Winter | Tuesday, December 21, 9:42 p.m. EST | Wednesday, December 22, 02:42 GMT |
For Central Time subtract one hour from the Eastern time, for Mountain Time two and for Pacific Time three. That moves one date: on the West Coast the September equinox falls at 11:02 p.m. on Wednesday, September 22. In the Southern Hemisphere the seasons are reversed, so the March equinox starts autumn there and the June solstice starts winter.
Why is the winter solstice on a different date in the US and the UK?
Because the moment falls in the middle of the night in Europe. The December solstice of 2027 is at 02:42 GMT on December 22. Five hours earlier on the clock, in New York, it is still 9:42 p.m. on December 21. Both dates are right; they describe the same instant.
The same thing happens with the other three events in other years and other time zones, which is why calendars sometimes disagree by a day.
What is an equinox?
The seasons exist because the Earth's axis is tilted by about 23.5 degrees. As the planet circles the Sun, first one hemisphere and then the other leans toward it. Distance has nothing to do with it: the Earth is closest to the Sun in the first week of January and farthest in the first week of July.
Twice a year the axis leans neither toward the Sun nor away from it. At that moment the Sun is directly above the equator, and that is an equinox. The word comes from the Latin aequus, "equal," and nox, "night."
Day and night are nearly equal on that date, but not exactly. According to the National Weather Service, the atmosphere bends sunlight, so the Sun is seen when it is in fact slightly below the horizon, and sunrise and sunset themselves take time. Around the equinox the day lasts about 12 hours 6.5 minutes at the equator, 12 hours 8 minutes at 30 degrees latitude and 12 hours 16 minutes at 60 degrees.
What is a solstice?
A solstice is the opposite point of the cycle: the moment when the tilt toward or away from the Sun is at its maximum. In June the Northern Hemisphere leans toward the Sun. The Sun reaches its highest noon position of the year, stands directly over the Tropic of Cancer at 23.5 degrees north, and the day is the longest of the year. In December the Sun is over the Tropic of Capricorn, and the north has its shortest day and longest night.
The word comes from the Latin solstitium, roughly "the Sun stands still." For a few days around the solstice the Sun's noon height hardly changes before it starts back the other way. The June date has its own page: summer solstice 2027.
Why do the dates change from year to year?
The Earth takes about 365.24 days to go around the Sun, and the calendar has 365. Each year the equinoxes and solstices therefore come about six hours later than the year before. A leap day pulls them back again. 2027 is the third year after a leap year, so its dates are among the latest of the four-year cycle, and 2028, a leap year, brings them forward.
| Event | 2026 | 2027 | 2028 |
|---|---|---|---|
| March equinox | March 20, 10:46 a.m. EDT | March 20, 4:25 p.m. EDT | March 19, 10:17 p.m. EDT |
| June solstice | June 21, 4:24 a.m. EDT | June 21, 10:11 a.m. EDT | June 20, 4:02 p.m. EDT |
| September equinox | September 22, 8:05 p.m. EDT | September 23, 2:02 a.m. EDT | September 22, 7:45 a.m. EDT |
| December solstice | December 21, 3:50 p.m. EST | December 21, 9:42 p.m. EST | December 21, 3:19 a.m. EST |
In UK time the 2028 March equinox is at 02:17 GMT on March 20, and the 2026 September equinox is at 01:05 BST on September 23.
Are the four seasons the same length?
No. The Earth's orbit is slightly elliptical, and the planet moves faster when it is nearer the Sun. NOAA puts the length of the astronomical seasons at between 89 and 93 days. In 2027, counting between the moments in the table, spring lasts about 92.7 days, summer about 93.7 and fall about 89.9. The northern summer is the longest season and the northern winter the shortest.
When do the seasons start for meteorologists?
Weather services do not use the equinoxes and solstices. Their seasons are built from whole calendar months, following the yearly temperature cycle:
- Spring: March 1 to May 31
- Summer: June 1 to August 31
- Fall: September 1 to November 30
- Winter: December 1 to the end of February
NOAA explains the reason: astronomical seasons start on different dates each year and vary in length, which makes climate statistics hard to compare. Seasons made of whole months are easy to total and to compare from one year to the next.
So both answers to "when is the first day of spring?" are correct. By the meteorological calendar it is March 1. By the astronomical one, in 2027, it is March 20.