When the day is longest and the night is shortest, at the summer solstice, Latvians celebrate Jāņi, St. John’s Eve, staying awake around bonfires or burning barrels raised high on poles so that singing, wandering neighbors can find the celebrations. Of the seasonal ancient Latvian celebrations, the summer solstice has most fully retained traditional activities that include preparations awaiting the great day and not only the festival itself. There are local variations, myriad nuances, and different traditions handed down within families. In one period the celebration was banned, in others organized; collective farms would organize collective Jāņi just as civil parishes and towns still do today. People pick their venue, celebrating with their extended family, among friends, or at a public celebration – or trying to take in more than one as the long twilight turns into brief night.
In the Latvian farmer’s calendar, Jāņi marks the first haymaking and follows the beginning of astronomical summer. Traditions in awaiting the holiday include the conclusion of spring labors, weeding, tending flowerbeds, learning folk songs, cleaning and tidying the home, making the special cheese in the shape of the solar disk, brewing beer, baking pīrāgi, and on the day preceding the festivities – decorating the farmstead with birch boughs, bouquets of flowers, garlands, oak branches and wreaths.
Scholars of religion connect Jāņi to solar cults and fertility rites, debating the extent of pre-Christian and Christian influences on the festival as we now know it. Austris Grasis, a researcher in Baltic folklore and the Latvian language, notes that the idea that Jānis as a divine son takes on some of the functions of the sun is insufficient in explaining the traditions; a solar cult alone cannot account for the figure of Jānis. Those rites connected to fire, awaiting the sunrise, dancing around the flames and some other aspects of the celebration can be connected to a solar cult, but an ancient, phallic fertility cult is another root of the Jāņi traditions. The birch boughs, the gathering of specific, magical plants, the dancing around the fields and use of the boughs at their perimeter to encourage fertility combined with the sexual symbolism in folk songs and the root of the incessantly repeated word līgo, which refers to swaying and swinging, make the erotic content of the festival clear.
Singing has a central place in the celebration. Many of the songs with the līgo refrain (leigū or rūto in the eastern region of Latgola) were originally sung by nubile girls, herders and ploughmen as they decorated the farmstead. The sounds of nature, especially lovely in the long, mystical twilights of the northern summer, blend with the traditional songs, giving the celebration the unique atmosphere that makes it the most loved Latvian holiday.
St. John’s Eve is also known as the Day of Grasses. The brief summer is at the peak of bloom, different plants having their traditional uses in folk medicine, divination, as decoration and in the weaving of wreaths. All guests are considered "children of Jānis," the host and hostess the father and mother of the "children." Beer – especially home-brewed, smoky beer – and the special golden cheese are essential to the celebration.