Summer Countdown

Astronomical summer starts at the June solstice, Monday, June 21, 2027, 10:11 AM on the US Eastern clock. It is one moment for the whole Earth, so the clock time depends on where you are:

Meteorological summer starts on Tuesday, June 1, 2027, 20 days before the June solstice, and runs for three whole months. DateMath takes the moment from the US Naval Observatory, in UTC to the minute, and the countdown above shows it in your own time zone.

In the US, summer has three starts: Memorial Day weekend, the unofficial one, with Memorial Day on Monday, May 31, 2027; June 1, the meteorological one; and the June solstice, June 21, 2027, the astronomical one. Labor Day, Monday, September 6, 2027, closes the unofficial summer, a few weeks before the September equinox ends the astronomical one.

Summer vacation from school follows each district's own calendar, so there is no single date to count down to. For a countdown to summer break, type "Summer break" in the day countdown, pick your last day of school and copy the link.

Summer 2027 runs from the June solstice to the September equinox, Thursday, September 23, 2027, 2:02 AM Eastern Time: 94 days on the Eastern calendar, or 93.66 days of 24 hours. Summer is the longest season in the Northern Hemisphere and winter the shortest, because Earth moves slowest when it is farthest from the Sun, in early July.

The June solstice in the coming years, from the US Naval Observatory's table:

The moment comes about 6 hours later each year and a leap year pulls it back by a day, so the date moves between two or three days of the month. The holidays by date tool lists every equinox and solstice on its date.

DateMath counts to the moment of the equinox or solstice, from the US Naval Observatory's table in UTC to the minute. That moment is the same everywhere, so the countdown reaches zero at once in every time zone, and DateMath shows it on your device's clock. Astronomical seasons start at these moments; meteorological seasons start on the 1st of March, June, September and December. The seasons are the Northern Hemisphere's; south of the equator they are reversed.

• Equinoxes and solstices. DateMath takes the moment of each equinox and solstice from the US Naval Observatory's table, in UTC to the minute. The holidays by date tool dates it on the US Eastern clock, and the season countdown shows it on your own clock. Near midnight the date differs between time zones. Source: USNO Earth's Seasons.
• Your device's local time. DateMath's countdowns read the current time from your device and count to the target in your own time zone. In the US, the standard time zones are set by 15 U.S.C. 261 and daylight saving time by 15 U.S.C. 260a (from 2:00 AM on the second Sunday in March to 2:00 AM on the first Sunday in November); your device applies them. Source: 15 U.S.C. 261, 15 U.S.C. 260a.
• US federal holidays. DateMath skips the 11 annual holidays of 5 U.S.C. 6103 on the days they are observed for federal employees, as the US Office of Personnel Management (OPM) lists them: a Saturday holiday on the Friday before, a Sunday holiday on the Monday after. Source: 5 U.S.C. 6103, OPM federal holidays.

DateMath's date math is tested against more than 100 cases worked out by hand. Every worked example and table on the site is computed with the same code the calculators run, so a page and its calculator can't disagree.