It is the summer solstice on 20 June and this marks the longest day in the northern hemisphere. The summer solstice happens between 20-22 June, although it is rare to be on 22 June.
A solstice occurs twice a year and marks the time when the sun is furthest away from the Equator. During the summer solstice the sun is at its most northern point, directly over the Tropic of Cancer, and the North Pole tilts directly towards the sun. This will happen at 10:34pm on Monday 20 June this year.
The summer solstice also marks the first day of summer in the astronomical calendar so holds special significance for many as it denotes a shift in seasons. The Earth tilts on its rotational axis at 23.4o and this tilt is what creates the seasons. The astronomical calendar marks the seasons by the earth’s tilt in relation to its orbit around the sun. In the northern hemisphere the Earth tilts towards the sun in summer and away from the sun in winter.