“Midsummer” can refer to the general period of June and July, the middle of the summer months, but it’s more commonly used to refer to the summer solstice around June 21. The date has always been important: the solstice is the longest day of the year, and after that the days slowly get shorter and the nights get darker.
Jumping the bonfire
All over Europe — indeed, over much of the world — midsummer is celebrated with bonfires that light up the shortest night of the year.
Celebrations can involve dancing around the bonfire, jumping over the bonfire, or simply feasting. The bonfires are lit to keep away evil spirits that come out on midsummer’s eve.
St. John’s Eve
Early Christian evangelizers complained that their flocks spent midsummer engaged in all kinds of lechery, lighting bonfires, eating, and drinking instead of going to church. One thing the Christians have always been good at is re-purposing pagan festivals as Christian holy days — and midsummer was no exception. Midsummer day became the feast day of St. John the Baptist, and midsummer’s eve became St. John’s Eve.
The celebrations have remained largely the same over the centuries, but the ideas behind them have been Christianized. The bonfires become a symbol of Christ, “a burning and shining light” (John 5:35). John Mirk, a historian of 15th century England, wrote that
“…in worship of St John the Baptist, men stay up at night and make three kinds of fires: one is of clean bones and no wood and is called a “bonnefyre”; another is of clean wood and no bones, and is called a wakefyre, because men stay awake by it all night; and the third is made of both bones and wood and is called, ‘St. John’s fire’.”
Some regions of the world have also added immersion in water to the festival, a sort of re-baptism in honor of St. John.