Summer 2027 starts with the summer solstice on Monday, June 21, 2027, at 10:10 a.m. EDT (14:10 UTC). It ends at the September equinox on Thursday, September 23, 2027, at 2:01 a.m. EDT, or Wednesday, September 22, on the West Coast.
Astronomical summer 2027 begins at the June solstice on the morning of Monday, June 21, 2027, the same calendar date across the United States, Europe, and most of Asia.
Meteorological summer starts three weeks earlier, on Tuesday, June 1, 2027, and many Americans treat Memorial Day, Monday, May 31, 2027, as the unofficial start.
The end of summer is where the dates split: the September equinox falls on Thursday, September 23, 2027, in the Eastern, Central, and Mountain time zones but on Wednesday, September 22, in Arizona, the Pacific time zone, Alaska, and Hawaii.
This page gives all three start dates, all three end dates, times for every US time zone, and the holidays, full moons, and the August 2, 2027, total solar eclipse that fall within the season.
Table of Contents
When does summer start in 2027?
Astronomical summer 2027 starts on Monday, June 21, 2027, at 10:10 a.m. Eastern Daylight Time, which is 14:10 UTC. At that moment, the Sun reaches its northernmost point in the sky, directly over the Tropic of Cancer.
The table below shows the start of summer 2027 in each US time zone and four international cities. The row marked with an asterisk falls on Tuesday, June 22, rather than Monday, June 21.
| Time zone | Local date | Local time |
|---|---|---|
| UTC | Monday, June 21, 2027 | 2:10 p.m. |
| Eastern (EDT) | Monday, June 21, 2027 | 10:10 a.m. |
| Central (CDT) | Monday, June 21, 2027 | 9:10 a.m. |
| Mountain (MDT) | Monday, June 21, 2027 | 8:10 a.m. |
| Arizona (MST) | Monday, June 21, 2027 | 7:10 a.m. |
| Pacific (PDT) | Monday, June 21, 2027 | 7:10 a.m. |
| Alaska (AKDT) | Monday, June 21, 2027 | 6:10 a.m. |
| Hawaii (HST) | Monday, June 21, 2027 | 4:10 a.m. |
| London (BST) | Monday, June 21, 2027 | 3:10 p.m. |
| Tokyo (JST) | Monday, June 21, 2027 | 11:10 p.m. |
| Sydney (AEST) | Tuesday, June 22, 2027* | 12:10 a.m. |
In Sydney, the same moment marks the start of winter, because the seasons are reversed in the Southern Hemisphere.
When does meteorological summer 2027 start?
Meteorological summer 2027 starts on Tuesday, June 1, 2027, and ends on Tuesday, August 31, 2027. The National Centers for Environmental Information (NCEI), part of NOAA, defines meteorological summer as June, July, and August.
Forecasters group seasons by whole months because astronomical seasons vary between 89 and 93 days, which makes year-to-year climate comparisons difficult. Meteorological summer always lasts 92 days.
The unofficial start of summer 2027
Memorial Day, Monday, May 31, 2027, is the unofficial start of summer in the United States, and Labor Day, Monday, September 6, 2027, is the unofficial end. Neither holiday is tied to the Sun or the weather.
They frame the period when many public pools, beaches, and seasonal businesses operate. The unofficial summer of 2027 spans 99 days, from Monday, May 31, to Monday, September 6, counting both holidays.
When does summer 2027 end?
Astronomical summer 2027 ends at the September equinox on Thursday, September 23, 2027, at 2:01 a.m. EDT, which is 06:01 UTC.
Summer 2027 lasts 93 days, 15 hours, and 51 minutes.
The last day of summer 2027 depends on your time zone. The table shows when summer ends in each US time zone. Rows marked with an asterisk end on Wednesday, September 22, rather than Thursday, September 23.
| Time zone | Local date | Local time |
|---|---|---|
| UTC | Thursday, September 23, 2027 | 6:01 a.m. |
| Eastern (EDT) | Thursday, September 23, 2027 | 2:01 a.m. |
| Central (CDT) | Thursday, September 23, 2027 | 1:01 a.m. |
| Mountain (MDT) | Thursday, September 23, 2027 | 12:01 a.m. |
| Arizona (MST) | Wednesday, September 22, 2027* | 11:01 p.m. |
| Pacific (PDT) | Wednesday, September 22, 2027* | 11:01 p.m. |
| Alaska (AKDT) | Wednesday, September 22, 2027* | 10:01 p.m. |
| Hawaii (HST) | Wednesday, September 22, 2027* | 8:01 p.m. |
| London (BST) | Thursday, September 23, 2027 | 7:01 a.m. |
For anyone in the Eastern, Central, or Mountain time zones, the last full day of summer 2027 is Wednesday, September 22, because summer ends in the first hours of Thursday. On the West Coast, summer ends late on Wednesday evening.
Three ways summer 2027 ends
Summer 2027 has three commonly used end dates spread across 22 days. The table compares them.
| Definition | Last day of summer 2027 | Next season begins |
|---|---|---|
| Meteorological (NOAA, Met Office) | Tuesday, August 31, 2027 | Meteorological fall, Wednesday, September 1, 2027 |
| Unofficial (Labor Day) | Monday, September 6, 2027 | Back-to-school and fall routines |
| Astronomical (equinox) | Wednesday, September 22, 2027 (Eastern) | Astronomical fall, Thursday, September 23, 2027 (Eastern) |
Summer start and end dates, 2027 to 2031
In US Eastern Time, summer starts on June 21 in 2027, 2030, and 2031 and on June 20 in 2028 and 2029.
The solstice moves about 5 hours and 50 minutes later each year, then jumps back almost a full calendar day in leap years such as 2028.
The table lists the start and end of astronomical summer for five years, calculated with Astronomy Engine. Independent sources may differ by one minute because of rounding.
| Year | Summer starts (UTC) | Summer starts (ET) | Summer ends (UTC) | Summer ends (ET) |
|---|---|---|---|---|
| 2027 | Mon, Jun 21, 14:10 | Mon, Jun 21, 10:10 a.m. | Thu, Sep 23, 06:01 | Thu, Sep 23, 2:01 a.m. |
| 2028 | Tue, Jun 20, 20:01 | Tue, Jun 20, 4:01 p.m. | Fri, Sep 22, 11:45 | Fri, Sep 22, 7:45 a.m. |
| 2029 | Thu, Jun 21, 01:48 | Wed, Jun 20, 9:48 p.m. | Sat, Sep 22, 17:37 | Sat, Sep 22, 1:37 p.m. |
| 2030 | Fri, Jun 21, 07:31 | Fri, Jun 21, 3:31 a.m. | Sun, Sep 22, 23:27 | Sun, Sep 22, 7:27 p.m. |
| 2031 | Sat, Jun 21, 13:17 | Sat, Jun 21, 9:17 a.m. | Tue, Sep 23, 05:15 | Tue, Sep 23, 1:15 a.m. |
In 2029, the solstice falls on June 21 in UTC but on the evening of June 20 across the United States, so the first day of summer 2029 differs between the US and Europe.
Astronomical summer vs. meteorological summer in 2027
The two definitions of summer 2027 start 20 days apart and end 23 days apart. Astronomical summer follows Earth’s position relative to the Sun. Meteorological summer follows the calendar and the temperature cycle.
| Attribute | Astronomical summer 2027 | Meteorological summer 2027 |
|---|---|---|
| Starts | Monday, June 21, 2027 | Tuesday, June 1, 2027 |
| Ends | Thursday, September 23, 2027 (ET) | Tuesday, August 31, 2027 |
| Length | 93 days, 15 hours, 51 minutes | 92 days |
| Basis | Sun at its northernmost point | Three whole calendar months |
| Used by | Astronomers, calendars, most media | NOAA, the UK Met Office, climate records |
| Next season begins | September equinox | Wednesday, September 1, 2027 |
Neither definition is the official one for the United States. No federal law sets the start of summer. Calendars and news outlets usually use the solstice, while weather services use June 1.
Why summer is the longest season
Astronomical summer is the longest season in the Northern Hemisphere, lasting 93 days, 15 hours, and 51 minutes in 2027.
Earth’s orbit is an ellipse, and Earth moves slowest near aphelion, its farthest point from the Sun. Aphelion 2027 falls on Monday, July 5, 2027, at 05:04 UTC, in the middle of Northern Hemisphere summer.
Because Earth is moving at its slowest, it takes longer to cross the summer quarter of its orbit. Summer 2027 is about 22 hours longer than spring 2027, which lasts 92 days, 17 hours, and 46 minutes, and more than four and a half days longer than winter.
Earth is farthest from the Sun during Northern Hemisphere summer. The heat comes from the high angle of sunlight and the long days, not from distance.
When is the hottest part of summer?
The warmest day of the year usually comes weeks after the summer solstice. According to NCEI’s analysis of the 1991–2020 US Climate Normals, the warmest day on average can fall anywhere from early June to as late as September or October, depending on location.
NCEI gives Terlingua, Texas, a normal warmest day of June 11, and San Francisco a normal warmest day of October 2, because the city’s marine layer keeps summer temperatures down.
This delay is called seasonal lag. Land and oceans keep absorbing heat for weeks after the Sun reaches its highest point, so temperatures keep rising after the days start getting shorter.
Longest day, earliest sunrise, and latest sunset
The longest day of 2027 in the Northern Hemisphere is Monday, June 21, 2027, but the earliest sunrise comes one to two weeks before it, and the latest sunset comes one to two weeks after.
The shift in solar noon through June moves sunrise and sunset times unevenly around the solstice.
The table shows the solstice daylight, earliest sunrise, latest sunset, and daylight lost by the end of summer for five US cities. Values were calculated with Astronomy Engine.
| City | Daylight on Mon, Jun 21, 2027 | Earliest sunrise | Latest sunset | Daylight on Wed, Sep 22, 2027 | Daylight lost |
|---|---|---|---|---|---|
| Miami | 13 h 45 m | Wednesday, June 9 (6:28 a.m) | Friday, July 2 (8:16 p.m) | 12 h 08 m | 1 h 37 m |
| New York City | 15 h 06 m | Monday, June 14 (5:24 a.m) | Sunday, June 27 (8:31 p.m) | 12 h 10 m | 2 h 56 m |
| Chicago | 15 h 14 m | Monday, June 14 (5:14 a.m) | Sunday, June 27 (8:29 p.m) | 12 h 10 m | 3 h 03 m |
| Seattle | 15 h 59 m | Wednesday, June 16 (5:11 a.m) | Friday, June 25 (9:11 p.m) | 12 h 11 m | 3 h 48 m |
| Anchorage | 19 h 22 m | Saturday, June 19 (4:20 a.m) | Tuesday, June 22 (11:42 p.m) | 12 h 16 m | 7 h 07 m |
All dates in the table are in 2027. Sunrise and sunset times rounded to the minute can hold steady for several days, so the listed date is the day of the absolute extreme.
Anchorage has the most daylight at the solstice and loses the most by the end of summer, more than seven hours.
What are the summer months?
The summer months in the Northern Hemisphere are June, July, and August under the meteorological definition.
Under the astronomical definition, summer 2027 covers the last 10 days of June, all of July and August, and the first 22 days of September in US Eastern Time.
In the Southern Hemisphere, the summer months are December, January, and February. Australia’s Bureau of Meteorology starts summer on December 1 because that date fits Australian temperature patterns better than the December solstice.
When does summer 2027 start in the UK and Australia?
Summer 2027 in the UK starts on Monday, June 21, 2027, at 3:10 p.m. BST under the astronomical definition, and on Tuesday, June 1, 2027, under the meteorological definition.
The Met Office uses meteorological seasons for its seasonal statistics and climate summaries, which places UK summer from June 1 to August 31.
In Australia, “summer 2027” can refer to two different seasons, because the Southern Hemisphere summer spans the new year. The table compares the summers that touch 2027 in Australia and the Northern Hemisphere.
| Region | Season | Meteorological dates | Astronomical start |
|---|---|---|---|
| United States | Summer 2027 | Tuesday, June 1, to Tuesday, August 31, 2027 | Monday, June 21, 2027, 10:10 a.m. EDT |
| United Kingdom | Summer 2027 | Tuesday, June 1, to Tuesday, August 31, 2027 | Monday, June 21, 2027, 3:10 p.m. BST |
| Australia | Summer 2026–2027 | Tuesday, December 1, 2026, to Sunday, February 28, 2027 | Tuesday, December 22, 2026, 7:50 a.m. AEDT |
| Australia | Summer 2027–2028 | Wednesday, December 1, 2027, to Tuesday, February 29, 2028 | Wednesday, December 22, 2027, 1:42 p.m. AEDT |
Australian summer 2027–2028 lasts 91 days under the meteorological definition, one day longer than usual, because February 2028 has 29 days.
Key summer 2027 dates
Two federal holidays in summer 2027 fall on weekends, so federal employees observe them on nearby weekdays.
Juneteenth, Saturday, June 19, 2027, is observed on Friday, June 18, and Independence Day, Sunday, July 4, 2027, is observed on Monday, July 5, under OPM’s holiday rules.
The table lists the holidays, full moons, and seasonal markers from Memorial Day to the September equinox.
| Event | Date | Note |
|---|---|---|
| Memorial Day | Monday, May 31, 2027 | Unofficial start of summer |
| Meteorological summer begins | Tuesday, June 1, 2027 | NOAA and Met Office definition |
| Strawberry Moon | Friday, June 18, 2027 | 8:45 p.m. EDT, last full moon of spring |
| Juneteenth | Saturday, June 19, 2027 | Federal holiday observed Friday, June 18 |
| Father’s Day | Sunday, June 20, 2027 | Third Sunday of June |
| Summer solstice | Monday, June 21, 2027 | 10:10 a.m. EDT |
| Independence Day | Sunday, July 4, 2027 | Federal holiday observed Monday, July 5 |
| Aphelion | Monday, July 5, 2027 | Earth farthest from the Sun, 05:04 UTC |
| Buck Moon | Sunday, July 18, 2027 | 11:45 a.m. EDT |
| Total solar eclipse | Monday, August 2, 2027 | Visible from Spain, North Africa, and the Middle East |
| Sturgeon Moon | Tuesday, August 17, 2027 | 3:29 a.m. EDT |
| Meteorological summer ends | Tuesday, August 31, 2027 | Fall begins September 1 |
| Labor Day | Monday, September 6, 2027 | Unofficial end of summer |
| Harvest Moon | Wednesday, September 15, 2027 | 7:04 p.m. EDT, falls before the equinox |
| September equinox | Thursday, September 23, 2027 | 2:01 a.m. EDT, end of summer |
In 2027, the Harvest Moon falls inside astronomical summer, seven days before the equinox, because the September full moon is closer to the equinox than the October one.
The August 2, 2027, total solar eclipse
The total solar eclipse of Monday, August 2, 2027, is the longest total eclipse visible from land between 1991 and 2114.
According to Space.com, the path of totality crosses Spain, Morocco, Algeria, Tunisia, Libya, Egypt, Sudan, Saudi Arabia, Yemen, and Somalia. Totality lasts up to 6 minutes and 23 seconds near Luxor, Egypt. The eclipse is not visible from the United States.
What summer 2027 is not
Summer 2027 does not start on Memorial Day or end on Labor Day under any astronomical or meteorological definition; those holidays mark the unofficial season only.
The first day of summer is also not the hottest day of the year, which arrives weeks later in most of the United States.
The longest day is not the day with the earliest sunrise or the latest sunset either. Finally, “summer” on this page refers to the season.
It does not cover summer break, which is a school holiday set by individual districts and colleges, or summer weather forecasts, which depend on regional conditions rather than the calendar.
Frequently asked questions
What is the first day of summer 2027?
The first day of summer 2027 is Monday, June 21, 2027, when the solstice occurs at 10:10 a.m. EDT. The date is the same in every US time zone and in the UK and Europe. Meteorological summer 2027 starts earlier, on Tuesday, June 1, 2027.
What is the last day of summer 2027?
The last full day of summer 2027 is Wednesday, September 22, 2027, in the Eastern, Central, and Mountain time zones, because the equinox arrives at 2:01 a.m. EDT on Thursday, September 23. On the West Coast, summer ends at 11:01 p.m. PDT on Wednesday, September 22.
Is June 1 the first day of summer?
June 1 is the first day of meteorological summer, used by NOAA and the UK Met Office for climate records. In 2027, it falls on a Tuesday. Astronomical summer 2027 starts later, on Monday, June 21, 2027, at the solstice. Both answers are correct under their own definitions.
How long is summer 2027?
Astronomical summer 2027 lasts 93 days, 15 hours, and 51 minutes, making it the longest season of the year. Meteorological summer lasts 92 days, from June 1 to August 31. The unofficial summer from Memorial Day to Labor Day 2027 spans 99 days, counting both holidays.
When is the longest day of 2027?
The longest day of 2027 in the Northern Hemisphere is Monday, June 21, 2027, the date of the summer solstice. New York City gets 15 hours and 6 minutes of daylight that day, and Anchorage gets 19 hours and 22 minutes. In the Southern Hemisphere, the same solstice marks the shortest day of the year.
When is summer in Australia in 2027?
Australian summer 2026–2027 runs from Tuesday, December 1, 2026, to Sunday, February 28, 2027. Australian summer 2027–2028 runs from Wednesday, December 1, 2027, to Tuesday, February 29, 2028. Both dates follow the Bureau of Meteorology’s definition, and both seasons span the new year.
Is Earth farther from the Sun in summer?
Yes. Earth is farthest from the Sun during Northern Hemisphere summer, at aphelion on Monday, July 5, 2027. Summer is warm because the Sun sits high in the sky and the days are long, which concentrates sunlight on the surface. Distance from the Sun has little effect on the seasons.
Sources:
- CalendarDate.com – Summer 2027
- NCEI – Meteorological Versus Astronomical Seasons
- NCEI – When to Expect the Warmest Day of the Year
- Space.com – Total solar eclipse 2027 guide
- OPM – Federal Holidays
- Bureau of Meteorology – Solstices, equinoxes and the seasons
- Met Office – When does autumn start?
