The four astronomical seasons of 2027 begin at the March equinox on Saturday, March 20 at 4:24 p.m. EDT, the June solstice on Monday, June 21 at 10:10 a.m. EDT, the September equinox on Thursday, September 23 at 2:01 a.m. EDT, and the December solstice on Tuesday, December 21 at 9:41 p.m. EST.
The four seasons of 2027 are not equal in length. Spring runs 92 days and 18 hours; autumn runs 89 days and 20 hours — a difference of nearly three days.
Earth’s orbit is elliptical, and the planet moves faster when closer to the Sun, which compresses the Northern Hemisphere’s autumn and winter relative to its spring and summer.
Table of Contents
Seasons 2027 dates and times
Each equinox and solstice is a single instant that occurs simultaneously everywhere on Earth.
Only the local clock reading changes. Times below are U.S. Eastern; published values vary by up to one minute between sources depending on rounding.
| Season begins | Event | Date | Time (Eastern) | Time (UTC) |
|---|---|---|---|---|
| Spring | March equinox | Saturday, March 20, 2027 | 4:24 p.m. EDT | 20:24 |
| Summer | June solstice | Monday, June 21, 2027 | 10:10 a.m. EDT | 14:10 |
| Autumn | September equinox | Thursday, September 23, 2027 | 2:01 a.m. EDT | 06:01 |
| Winter | December solstice | Tuesday, December 21, 2027 | 9:41 p.m. EST | 02:41, December 22 |
The December solstice falls on December 22 in UTC and across Europe, Asia and Australia, but on December 21 in every U.S. time zone.
Both describe the same instant.
Season lengths in 2027
| Season | Runs from | Runs to | Length |
|---|---|---|---|
| Spring 2027 | March 20 | June 21 | 92 days, 17 hours |
| Summer 2027 | June 21 | September 23 | 93 days, 16 hours |
| Autumn 2027 | September 23 | December 21 | 89 days, 20 hours |
| Winter 2027–28 | December 21 | March 19, 2028 | 89 days, 0 hours |
Summer is the longest season in the Northern Hemisphere by nearly four days over winter.
Earth reaches aphelion, its farthest point from the Sun, in early July, and orbital speed is lowest there.
Seasons 2027 in the Southern Hemisphere
The same four instants mark the opposite seasons south of the equator.
The March equinox begins autumn in Australia, Argentina and South Africa; the June solstice begins winter; the September equinox begins spring; the December solstice begins summer.
The length asymmetry reverses with it. Southern Hemisphere summer is the short season, running 89 days and 20 hours from December to March, which is why Southern Hemisphere summers are marginally shorter and, all else equal, warmer per day than Northern Hemisphere summers.
Astronomical seasons are not meteorological seasons
Two definitions are in common use and they disagree by roughly three weeks.
| Astronomical | Meteorological | |
|---|---|---|
| Spring 2027 | March 20 – June 21 | March 1 – May 31 |
| Summer 2027 | June 21 – September 23 | June 1 – August 31 |
| Autumn 2027 | September 23 – December 21 | September 1 – November 30 |
| Winter 2027–28 | December 21 – March 19 | December 1 – February 28 |
| Defined by | Earth’s position in orbit | Fixed calendar blocks |
| Length | Varies, 89 to 94 days | Fixed, 90 to 92 days |
| Used by | Almanacs, calendars, sky guides | Meteorologists, climate statistics |
Meteorologists use fixed calendar blocks so that seasonal statistics compare cleanly year to year.
When a forecaster says a season was the warmest on record, they mean the meteorological block, not the solstice-to-equinox window.
By meteorological reckoning, winter is already three weeks old when the December solstice arrives.
Daylight saving time 2027
Daylight saving time is not a season boundary, but it sits close enough to the March equinox to be confused with one.
| Event | Date | Time | Effect |
|---|---|---|---|
| DST begins | Sunday, March 14, 2027 | 2:00 a.m. local | Clocks forward, 23-hour day |
| DST ends | Sunday, November 7, 2027 | 2:00 a.m. local | Clocks back, 25-hour day |
The schedule is set by 15 U.S.C. 260a as amended by the Energy Policy Act of 2005: the second Sunday in March to the first Sunday in November.
Hawaii and most of Arizona do not observe it; the Navajo Nation, which extends into Arizona, does.
Daylight saving time begins six days before the spring equinox in 2027. The two are unrelated — one is a legal convention, the other an orbital position.
Why the equinox is not exactly twelve hours of daylight
At the equinox the Sun crosses the celestial equator, and the common description is that day and night are equal.
They are not, quite. Two effects extend daylight by six to eight minutes at mid-latitudes:
- Sunrise and sunset are defined by the Sun’s upper edge crossing the horizon, not its centre, which adds daylight at both ends.
- Atmospheric refraction bends sunlight over the horizon, making the Sun visible before it has physically risen and after it has physically set.
The date on which day and night are genuinely equal is called the equilux, and it falls a few days before the March equinox and a few days after the September equinox, varying with latitude.
At the equator it does not occur at all.
Frequently asked questions
When is the first day of spring 2027?
Saturday, March 20, 2027, at 4:24 p.m. EDT. That is the astronomical definition, set by the March equinox. By the meteorological definition, spring 2027 began on Monday, March 1. Both are in common use and neither is wrong; they answer different questions.
Why do the seasons have different lengths?
Because Earth’s orbit is an ellipse rather than a circle, and orbital speed varies with distance from the Sun. Earth moves fastest at perihelion in early January and slowest at aphelion in early July. That makes Northern Hemisphere summer the longest season at 93 days and 16 hours in 2027, and winter the shortest at 89 days.
Is the December solstice on December 21 or December 22 in 2027?
December 21 in every U.S. time zone, December 22 in UTC and most of Europe and Asia. The instant is 02:41 UTC on December 22, which is 9:41 p.m. EST on December 21. The solstice date drifts about six hours later each year, then snaps back with each leap year, so the calendar date alternates between the 21st and 22nd.
