The 2019 summer solstice – also known as midsummer – falls in the Northern Hemisphere this week. It occurs when one of the Earth’s poles reaches its maximum tilt toward the Sun. This happens twice yearly, once in the Northern Hemisphere and once in the Southern Hemisphere. This year summer solstice falls on Friday, June 21 at 4.54pm BST.
What does summer solstice mean?
The summer solstice is the longest day of the year in the northern hemisphere – as it the day on which that region receives the most hours of sunlight.
On this day there will be 16 hours and 38 minutes of daylight in the UK.
The Sun will rise at 4.43am before setting at 9.21pm.
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This is because the Sun will appear at its highest in the northern sky, directly over the Tropic of Cancer.
On the other side of the world in the Southern Hemisphere, it will be the shortest day of the year.
This area will have the least hours of sunlight for that day.
The reason solstices occur is because the Earth is tilted on its axis by 23.5 degrees relative to the plane of its orbit.
Each hemisphere consequently experiences six months tilted toward the Sun and the other six tilted away.
The differences in the tilt mean both hemispheres are struck by varying levels of radiation from the Sun over the course of the year.
This, in turn, creates the seasons of Spring, Summer, Autumn and Winter.
In astrological terms, the June solstice marks the end of spring and start of summer for the northern hemisphere.
And this season will end with the autumn equinox, which this year falls on September 23.
However, according to the meteorological calendar, summer began on June 1 and will end on August 31.
The meteorological year is defined differently to the astrological year, taking the months of the calendar and annual temperature cycles into account.
Summer is June to August, autumn is September to November, winter is December to February and spring is March to May.