The summer solstice is the longest day of the year and in the northern hemisphere, it can fall on different dates from year to year, between 20 and 22 June. In the southern hemisphere it is between December 20 and December 23. In the Celtic nations in 2016, it falls on Monday 20 June. The winter solstice which is the shortest day of the year falls between 20 and 22 December. In the Celtic homelands in 2016, this will fall on 21 December .
Both the summer and and winter solstices have a particular significance to Celtic peoples. Many ancient stone monuments align to the solstices. The Druids, the Celtic high priests led ritual celebrations during the solstice. Bonfires lit the night skies at the time of the summer solstice and to this day it remains a time of celebration and significance in the Celtic calendar. Recognising the Sun as the star that is by far the most important source of energy for life on Earth