After the countless sunny days we have enjoyed in May, it may feel as though summer arrived a while ago.
Last month brought the first stages of eased lockdown restrictions, with people in Scotland now able to meet up outdoors with friends and loved ones, and enjoy socially distanced sunbathing and picnics.
However, astronomically speaking, the summer technically doesn't start until the onset of June solstice.
What is June solstice?
The June solstice is also known as the aestival solstice, or the northern solstice.
A solstice is an event that occurs twice annually, in the summer and winter.
It happens when one of the Earth's poles is titled as much as it possibly can be, toward the Sun, causing the Sun to reach its highest position in the sky and provide the longest period of daylight for that year.
For example, when the Earth’s North Pole is tilted toward the Sun in June, the northern hemisphere receives more sunlight and this marks the onset of summer for that part of the globe.
However, in the Southern Hemisphere the June solstice marks the start of winter.
The summer solstice occurs each June, falling on 20 to 22 depending on the year, while the winter solstice occurs on 21 December, marking the shortest day of the year.
When is this year’s June solstice?
This year’s June solstice falls on Saturday 20 June at 10.43pm.
What is midsummer?
Fans of Shakespeare will be well aware of this term, which features in the title of his famous play Midsummer Night's Dream.
Confusingly, while the June solstice marks the astronomical start of summer, it is also widely known as midsummer - and marks the middle of summer, since from that point onwards the days start to get shorter.
How else do we mark the onset of summer?
There are actually two separate definitions of the start of summer.
While the astronomical definition of summer is the June solstice, the meteorological definition of summer is much more straightforward.
This is based on the Gregorian calendar and states that summer begins on 1 June and ends on 31 August.
The meteorological calendar divides the year into four concise seasons consisting of three full months each.
It was made in 1780 by the Societas Meteorologica Palatina, an early international organisation for meteorology, in order to simplify the process of comparing seasonal and monthly data.
When does astronomical summer end?
The astronomical summer ends with the autumnal equinox.
This marks one of two points in the year where the equator is the closest part of Earth to the sun.
The other occasion is the spring equinox. The word equinox derives from the Latin for "equal night".
This year’s autumnal equinox, and the end of astronomical summer, lands on Tuesday, 22 September.