When is the Longest Day of the Year?
The longest day of the year, referred to as the summer solstice, occurs in the Northern Hemisphere on June 20th or 21st each year. The name "solstice" comes from the Latin word "sol" which means sun and sistere which means standstill. The day occurs when the sun is precisely overhead the Tropic of Cancer, which is the furthermost northern point the sun can reach when revolving around the earth. On this day, the sun does not rise from the east and set in the west as it normally does. Instead, it rises to the north of east and sets to the north of west hence being observable for more hours.
Since the solstice occurs very early in the morning in the UTC, Europe, America, and West Asia experience the longest hours of sunlight on June 20th while East Asia and Australia experience it on June 21st. However, there are extreme situations when the solstice can occur on June 22nd. The last solstice occurring on June 22nd was in 1975 and it is likely to happen again in 2203. The day of the June solstice marks the commencement of meteorological summer in the Northern Hemisphere and the start of the metrological winter in the Southern Hemisphere.
How Long Does the Longest Day Last?
The duration of the longest day of the year is dependent on the latitude of the specified place on the earth. The higher the latitude the longer the day, and the lower the latitude the shorter the day. In the northern and southern hemispheres, the solstice lasts for 24 hours where sunrise and sunset do not happen. Therefore, those in the Arctic Circle experience 24 hours of sunrise (midnight sun) while those in the Antarctic Circle experience 24 hours of darkness (polar night).
Although June 21 is considered the longest day of the year, it is not the day of the earliest sunrise. In fact, the week preceding the solstice has an earlier sunrise by one minute as compared to the actual day. The day will always be determined based on the calendar system in use. Most western countries apply the Gregorian calendar, which has 365 days in a standard year or 366 in a leap year.
Solstice in Culture
Over the centuries, the June solstice has inspired countless festivals, religious holidays and midsummer celebrations. The world’s oldest evidence of the summer solstice is the Stonehenge megalithic structure in England. Historians have used the pre-historic monument to explain how the early man used the day to mark their calendar. They denote that the creators of the Stonehenge used the solstice as their starting point when counting the number of days in a year.
The Newgrange, an antique passageway tomb in Ireland built 1000 years before the Stonehenge attracts thousands of visitors from across the globe for the annual winter solstice affair. The inventors of the tomb constructed a tiny roof-box that allows sunlight to illuminate through the tunnel on the morning of the winter solstice and light up the room commemorating the longest night of the year.