What is the summer solstice?
The summer solstice in the northern hemisphere, in astronomical terms, marks the point in the year where the sun is directly over the Tropic of Cancer at 23.5 degrees north.
During the spring and autumn equinoxes, the sun is directly over the equator and during the winter solstice (for the northern hemisphere), the sun is directly over the Tropic of Capricorn.
This reflects the fact that the Earth is tilted on its axis at that angle. If it wasn’t, there would be no seasons – there would be six months of winter and six months of summer everywhere.
During the months between December and June, the northern hemisphere is pointed towards the sun and the southern hemisphere is pointed away from the sun.
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Since the sun is directly over the Tropic of Cancer, it is also at its highest point in the sky at any point in the northern hemisphere. The opposite is true in the southern hemisphere.
The longest day in the northern hemisphere is the shortest day in the southern hemisphere and vice-versa.
What is its significance?
The summer solstice marks the point where there is more daylight than any other day of the year. After that, the days start getting shorter until the shortest day of the year on December 21st.
Why is the summer solstice important in Ireland?
Ancient peoples were fascinated by the sky. They drew constellations from the patterns and saw portents everywhere in the sky. The sun and the moon were deities. In prehistoric times, the movements of the sun and moon were not just of ceremonial importance - they determined the cycles of agriculture.
The Celtic people built their calendars around the movements of the sun and moon in the sky.
While Newgrange was rediscovered in the 17th century, its exact significance as an effective calendar was not recognised until December 21st, 1967, when archaeologist Dr Michael O’Kelly made a remarkable discovery.
He confirmed local lore that the rising midwinter sun passed through the roof box above the entrance to Newgrange, flooding the burial chamber inside with light.
As they knew when the winter solstice fell, it followed that they also knew the date of the summer solstice.
How is the summer solstice marked in Ireland?
The largest event in Ireland is the gathering at the Hill of Tara, Co Meath, to watch sunrise on June 21st.
Many camp overnight in anticipation of a very early start. They will generally need to be up by 4.45am to watch the sun rise over the eastern horizon. There are other gatherings around the country, though not as large.
Traditionally, the summer solstice has been marked by bonfire night on June 23rd, on the eve of St John’s Day (June 24th).
