Saint Jonas' Festival, also known as Rasos (Dew Holiday), Joninės, Kupolė, Midsummer Day or Saint John's Day) is a midsummer folk festival celebrated on June 24 all around Lithuania. While midsummer day is celebrated throughout Europe, many Lithuanians have a particularly lively agenda on this day. The traditions include singing songs and dancing until the sun sets, telling tales, searching to find the magic fern blossom at midnight, jumping over bonfires, greeting the rising midsummer sun and washing the face with a morning dew, young girls float flower wreaths on the water of river or lake.

Once upon a time the Balts, the ancestors of the Lithuanians, celebrated the feast of Rasos by offering sacrifices to the pagan gods, and priestesses incited the altar fire. When Christianity came to Lithuania, it brought with it the celebration of Saint John's Day and since then, it has been celebrated in Lithuania, being called Joninės (St. John's) in the local language. Lithuanians with the names Jonas, Jonė, Janina receive many greetings from their family, relatives and friends.