The longest day of the year — also called the summer solstice — is the day when the sun reaches its highest point in the sky and daylight lasts longer than on any other day of the year. In the Northern Hemisphere this falls around June 20 or 21. In the Southern Hemisphere the roles are reversed: June is midwinter, and the longest day falls around December 21 or 22.
The exact date shifts slightly from year to year because the solar year is about 365.25 days long — not a clean 365. Leap years pull the solstice a day earlier; the pattern then slowly drifts back.
How much daylight you get on the summer solstice depends almost entirely on your latitude. The closer you are to a pole, the more extreme the swing between your longest and shortest day. Near the equator, there is almost no difference at all.
| Location | Latitude | Day length at summer solstice |
|---|---|---|
| Tromsø, Norway | 70°N | 24 h 00 min (midnight sun — sun does not set) |
| London, UK | 51°N | ~16 h 38 min |
| New York, USA | 41°N | ~15 h 05 min |
| Singapore | 1°N | ~12 h 12 min |
| Sydney, Australia | 34°S | ~9 h 53 min (their shortest day) |
Above the Arctic Circle (66.5°N), the sun does not set at all around the solstice. This is the famous midnight sun. At the other extreme, locations above the Antarctic Circle experience polar night — continuous darkness — at this same time of year.
The word solstice comes from Latin sol (sun) + sistere (to stand still) — at this moment the sun's northward journey pauses before reversing. From the day after the summer solstice, days in the Northern Hemisphere begin to shorten again, though the change is imperceptibly slow at first: only a minute or two per day in late June and July. By the time the autumn equinox arrives in late September, the rate of shortening has accelerated to several minutes per day. The cycle ends at the winter solstice in December, when the shortest day of the year arrives.
Counterintuitively, the hottest weather of the year typically arrives after the solstice — in July and August in the Northern Hemisphere — because it takes time for the land and oceans to absorb and re-radiate the solar energy that has been building since spring.
Cultures across the world have marked the summer solstice for thousands of years. In Scandinavia, midsummer is one of the most celebrated holidays of the year — bonfires are lit, flower crowns worn, and people dance around maypoles. Stonehenge in England aligns precisely with the midsummer sunrise and has drawn visitors for this moment for over 4,000 years. In China, the summer solstice is celebrated as Xiazhi, a day associated with yin energy beginning to grow. Indigenous cultures across the Americas, from the Inca to the Lakota, built astronomical monuments oriented to solstice sunrises and sunsets.
If you are south of the equator, the June solstice is your winter solstice — your shortest day, not your longest. Your longest day falls in December. The seasons are simply mirrored: while London enjoys 16+ hours of daylight in June, Sydney gets fewer than 10.
Use the tool on the homepage to see the exact sunrise, sunset, and day length for your location today — and on any date you choose.