Significance of the summer solstice:

In pre-historic times, summer was a joyous time of the year for those Aboriginal people who lived in the northern latitudes. The snow had disappeared; the ground had thawed out; warm temperatures had returned; flowers were blooming; leaves had returned to the deciduous trees. Some herbs could be harvested, for medicinal and other uses. Food was easier to find. The crops had already been planted and would be harvested in the months to come. Although many months of warm/hot weather remained before the fall, they noticed that the days were beginning to shorten, so that the return of the cold season was inevitable. 

The first (or only) full moon in June is called the Honey Moon. Tradition holds that this is the best time to harvest honey from the hives.  

This time of year, between the planting and harvesting of the crops, was the traditional month for weddings. This is because many ancient peoples believed that the "grand [sexual] union" of the Goddess and God occurred in early May at Beltaine. Since it was unlucky to compete with the deities, many couples delayed their weddings until June. June remains a favorite month for marriage today. In some traditions, "newly wed couples were fed dishes and beverages that featured honey for the first month of their married life to encourage love and fertility. The surviving vestige of this tradition lives on in the name given to the holiday immediately after the ceremony: The Honeymoon." ₁₄

Midsummer celebrations in ancient and modern times:

Most societies in the northern hemisphere, ancient and modern, have celebrated a festival on or close to Midsummer:

• Ancient Celts: Druids, the priestly/professional/diplomatic corps in Celtic countries, celebrated Alban Heruin ("Light of the Shore"). It was midway between the spring Equinox (Alban Eiler; "Light of the Earth") and the fall Equinox (Alban Elfed; "Light of the Water"). "This midsummer festival celebrates the apex of Light, sometimes symbolized in the crowning of the Oak King, God of the waxing year. At his crowning, the Oak King falls to his darker aspect, the Holly King, God of the waning year..." ₁₃ The days following Alban Heruin form the waning part of the year because the days become shorter.
• Ancient China: Their summer solstice ceremony celebrated the earth, the feminine, and the yin forces. It complemented the winter solstice which celebrated the heavens, masculinity and yang forces.
• Ancient Gaul: The Midsummer celebration was called Feast of Epona, named after a mare goddess who personified fertility, sovereignty and agriculture. She was portrayed as a woman riding a mare.
• Ancient Germanic, Slav and Celtic tribes in Europe: Ancient Pagans celebrated Midsummer with bonfires. "It was the night of fire festivals and of love magic, of love oracles and divination. It had to do with lovers and predictions, when pairs of lovers would jump through the luck-bringing flames..." It was believed that the crops would grow as high as the couples were able to jump. Through the fire's power, "...maidens would find out about their future husband, and spirits and demons were banished." Another function of bonfires was to generate sympathetic magic: giving a boost to the sun's energy so that it would remain potent throughout the rest of the growing season and guarantee a plentiful harvest. ₆
• Ancient Rome: The festival of Vestalia lasted from JUN-7 to JUN-15. It was held in honor of the Roman Goddess of the hearth, Vesta. Married women were able to enter the shrine of Vesta during the festival. At other times of the year, only the vestal virgins were permitted inside.
• Ancient Sweden: A Midsummer tree was set up and decorated in each town. The villagers danced around it. Women and girls would customarily bathe in the local river. This was a magical ritual, intended to bring rain for the crops.
• Christian countries: After the conversion of Europe to Christianity, the feast day of St. John the Baptist was set as JUN-24. It "is one of the oldest feasts, if not the oldest feast, introduced into both the Greek and Latin liturgies to honour a saint." ₁₆ Curiously, the feast is held on the alleged date of his birth. Other Christian saints' days are observed on the anniversary of their death. The Catholic Encyclopedia explains that St. John was "filled with the Holy Ghost even from his mother's womb...[thus his] birth...should be signalized as a day of triumph." ₁₆ His feast day is offset a few days after the summer solstice, just as Christmas is fixed a few days after the winter solstice. ₁ "Just as John was the forerunner to Jesus, midsummer forecasts the eventual arrival of" the winter solstice circa DEC-21. 
• Essenes: This was a Jewish religious group active in Palestine during the 1st century CE. It was one of about 24 Jewish groups in the country -- the only one that used a solar calendar. Other Jewish groups at the time included the Sadducees, Pharisees, Zealots, followers of John, and followers of Yeshua (Jesus). Archaeologists have found that the largest room of the ruins at Qumran (location of the Dead Sea Scrolls) appears to be a sun temple. The room had been considered a dining room by earlier investigators, in spite of the presence of two altars at its eastern end. At the time of the summer solstice, the rays of the setting sun shine at 286 degrees along the building's longitudinal axis, and illuminate the eastern wall. The room is oriented at exactly the same angle as the Egyptian shrines dedicated to the sun. Two ancient authorities -- the historian Josephus and the philosopher Filon of Alexandria -- had written that the Essenes were sun worshipers. Until recently, their opinion had been rejected by modern historians. ₁₉
• Native Americans:
  • The Natchez tribe in the southern U.S. "worshiped the sun and believed that their ruler was descended from him. Every summer they held a first fruits ceremony." Nobody was allowed to harvest the corn until after the feast. ₂
  • Males in the Hopi tribe dressed up as Kachinas - the dancing spirits of rain and fertility who were messengers between humanity and the Gods. At Midsummer, the Kachinas were believed to leave the villages to spend the next six months in the mountains, where they were believed to visit the dead underground and hold ceremonies on their behalf. ₂
  • Native Americans have created countless stone structures linked to equinoxes and solstices. Many are still standing. One was called Calendar One by its modern-day discoverer. It is in a natural amphitheatre of about 20 acres in size in Vermont. From a stone enclosure in the center of the bowl, one can see a number of vertical rocks and other markers around the edge of the bowl "At the summer solstice, the sun rose at the southern peak of the east ridge and set at a notch at the southern end of the west ridge." The winter solstice and the equinoxes were similarly marked. ₅
  • The Bighorn Medicine Wheel west of Sheridan, WY is perhaps the most famous of the 40 or more similar "wheels" on the high plains area of the Rocky Mountains. Mostly are located in Canada. At Bighorn, the center of a small cairn, that is external to the main wheel, lines up with the center of the wheel and the sun rising at the summer equinox. Another similar sighting cairn provides a sighting for three dawn-rising stars: Aldebaran, Rigel and Sirius. A third cairn lines up with fourth star: Fomalhaut. The term "medicine wheel" was coined by Europeans; it was a term used to describe anything native that white people didn't understand. ₁₇
• Neopaganism: This is a group of religions which are attempted re-constructions of ancient Pagan religions. Of these, Wicca is the most common; it is loosely based partly on ancient Celtic beliefs and practices. Wiccans recognize eight seasonal days of celebration. Four are minor sabbats and occur at the two solstices and the two equinoxes. The other are major sabbats which happen approximately halfway between an equinox and solstice. The summer solstice sabbat is often called Midsummer or Litha. Wiccans may celebrate the sabbat on the evening before, at sunrise on the morning of the solstice, or at the exact time of the astronomical event.
  
  "Midsummer is the time when the sun reaches the peak of its power, the earth is green and holds the promise of a bountiful harvest. The Mother Goddess is viewed as heavily pregnant, and the God is at the apex of his manhood and is honored in his guise as the supreme sun." ₁₂
  
  It is a time for divination and healing rituals. Divining rods and wands are traditionally cut at this time.
• Prehistoric Europe: Many remains of ancient stone structures can be found throughout Europe. Some date back many millennia BCE. Many appear to have religious/astronomical purposes; others are burial tombs. These structures were built before writing was developed. One can only speculate on the significance of the summer solstice to the builders. Perhaps the most famous of these structures is Stonehenge, a megalith monument on Salisbury Plain in Wiltshire. It was built in three stages, between circa 3000 and 1500 BCE. "The circular bank and ditch, double circle of 'bluestones' (spotted dolerite), and circle of sarsen stones (some with white lintels), are concentric, and the main axis is aligned on the midsummer sunrise--an orientation that was probably for ritual rather than scientific purposes.₄ Four "station stones" within the monument form a rectangle whose shorter side also points in the direction of the midsummer sunrise. ₁₅

The dates and times of the summer solstice:

The exact date varies from year to year and may occur between the 20th and 23rd of June. 

The dates and times for 1999 to 2004 were provided by The Dome of the Sky web site. ₉ However, this site is not working as of 2005-APR-05. The dates and times for 2005 to 2009 were copied from Archaeostronomy.com. ₂₀ An online "Easy Date Converter" calculates the dates and times of the equinoxes and solstices within 20 seconds. ₂₁

Times are in UT (Universal Time). This used to be called Greenwich Mean Time or GMT. In North America, you can find your local time by subtracting:

• 2 hours 30 minutes for Newfoundland daylight savings time
• 3 hours for ADT
• 4 hours for EDT
• 5 hours for CDT
• 6 hours for MDT
• 7 hours for PDT
• 8 hours in AKDT (Alaska)
• 9 hours in ADT (Aleutian Islands)
• 10 hours in HST (Hawaii) ₁₀

The ancients did not have access to modern mathematical algorithms to calculate the date and time of the solstice. To the unaided eye, the sun would seem to set/rise at the same location on the horizon for about five days before and after the actual solstice. Ancient people would record the days when the sun rise or set was noticeably different from the extreme position, and interpolate the probable day of the solstice. They then used a variety of techniques to display future solstices:

• A carved or painted symbol, or some other marker, would be located at the end of a long passage that was exposed to sunrise or sunset on the solstice. It would be illuminated by the rising or setting of the sun on the day of the solstice. Alternatively, a hole in the roof of a structure would allow the noonday sun to shine onto a marker set into the floor.
• In temperate zones, the shadow of an upright pillar would be observed at noontime at the summer solstice. The shadow would be shortest on that day.
• The point on the horizon where the sun set and rose would be observed from a fixed location. A remote marker would indicate where the sun rose or set on the solstice. ₃