Solstice ushers in start of summer 2025 on Saturday

Arab News

20-06-2025

RIYADH: The summer solstice, which marks the season's astronomical beginning, will take place on Saturday, June 21, according to the Jeddah Astronomical Society.
The Kingdom will witness the solstice at 5.42 a.m. Makkah time, when the sun will be directly overhead above the Tropic of Cancer, latitude .
The skies of the Kingdom and the rest of the Northern Hemisphere will witness the summer solstice Saturday at 5:42 am Makkah time.
At this moment, the sun will be directly overhead above the Tropic of Cancer, latitude 23.5 degrees north. This year, the summer will last for 93 days.
Majed Abu Zahra, head of the Jeddah Astronomical Society, said: 'On this day, the sun rises from the far northeast and sets in the far northwest. At noon, the shadows of objects are the shortest of the year, and the sun's apparent path takes its highest arc northward, placing it at its highest altitude in the sky during the year, especially in areas north of the equator.'
The summer solstice occurs when the sun reaches its apparent northernmost point in the sky. This coincides with the Earth reaching a position in its orbit where its axis is tilted at the maximum angle (23.5 degrees) toward the sun, causing the longest day and shortest night of the year in the Northern Hemisphere. In the Southern Hemisphere, the situation is reversed.
Abu Zahra added: 'The summer solstice does not occur on the same day every year, but rather between June 20 and 22, due to the difference between the calendar year (365 days) and the tropical year (365.2422 days), along with the gravitational effects of the moon and planets and the slight fluctuations in the Earth's rotation, which are compensated for by adding a leap day every four years.'
He said it was important to differentiate between the astronomical summer and climatic summer.
Meteorologists consider summer to extend from June 1 to August 31, while in astronomy, summer begins when the sun reaches its maximum altitude — the day of the summer solstice.
Abu Zahra said although this was the longest day of the year in terms of the number of hours of sunlight, it was not necessarily the hottest.
This is because the oceans, land and atmosphere take time to absorb and store solar energy, and then release it again. This delay in the perception of heat is known as 'seasonal lag,' so temperatures typically peak in July or August.
Ancient Greek scholars, led by Eratosthenes, used their observations on the summer solstice to calculate the Earth's circumference with amazing accuracy using simple geometric principles.
After the summer solstice, the sun will appear to move southward again in the sky, and daylight hours will gradually decrease until the autumnal equinox on Sept. 22.