Sant Joan in Spain marks the start of the summer. This is is the midsummer solstice celebration, which is the day that has the longest period of daylight in the year (not to be confused with the "Equinox" days, which are the days when the day and night are of equal length.
The Nit de Sant Joan celebrations in Spain and Barcelona are on the evening of the 23rd June. The next day is 24th June which is Saint John's day and a public holiday in Catalonia and Spain. The Sant Joan festivals and fiestas are from sunset on 23/6 to sunrise on 24/6 on the eve of Saint John's day.
The Sant Joan festival is often called "La Nit de Sant Joan" – the night of Saint John. The fiestas are also called "verbenas" or "revetllas."The most important element of the festival of Sant Joan is fire. The flame to light the fires is called the "Flama del Canigó," which is taken to different villages every year.