UAE

What to expect as UAE marks its longest day since 1796 on June 20

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A solstice occurs when the sun reaches its most northerly or southerly point relative to the celestial equator on the celestial sphere.
Image Credit: WAM

SHARJAH: The UAE will experience its longest day since 1796 on June 20, with daylight hours clocking 13 hours and 48 minutes.

This will be the result of an earlier summer solstice this year.

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Occurring on June 20 at 12:51am Gulf Standard Time (GST), this marks the earliest solstice since 1796 for most countries around the world. Similar variations in solstice timing can be expected in future leap years too, according to WAM.

What is a solstice?

A solstice occurs when the sun reaches its most northerly or southerly point relative to the celestial equator on the celestial sphere.

Twice-a-year phenomenon
The summer solstice occurs when one of Earth’s poles has its maximum tilt toward the Sun. It happens twice yearly, once in each hemisphere (Northern and Southern). For that hemisphere, the summer solstice is the day with the longest period of daylight and shortest night of the year, when the Sun is at its highest position in the sky. At either pole there is continuous daylight at the time of its summer solstice. The opposite event is the winter solstice.

As Ibrahim Al Jarwan, Board Chairman of the Emirates Astronomical Society and member of the Arab Union for Space and Astronomy Sciences, explained, during the summer solstice, the sun is directly overhead at the Tropic of Cancer, its northernmost point. In areas directly below the sun, such as the southern regions of the UAE, there will be no shadow at noon. Shadows at noontime will also be shorter across the Arabian Peninsula, with the shortest shadow occurring in the entire Northern Hemisphere.

Temeperatures on the day

Al Jarwan added that temperatures are expected to range between 41 and 43 degrees Celsius during the day and 26 and 29 degrees Celsius at night, with generally dry conditions and active winds. This is expected to be the case during the first half of summer, which runs from June 21 to August 10.

The second half of summer, spanning from August 11 to the autumnal equinox on September 23, is characterised by an influx of high humidity, persistent high temperatures, and the activation of moist Kos winds. These winds invigorate the formation of cumulonimbus clouds over mountainous regions and their surroundings, leading to thunderstorms.