Sunday Will Be the Longest Day of the Year in the UAE
Nearly 14 hours of daylight will mark the UAE’s longest day as astronomical summer officially starts.
The UAE will see its longest day of the year on Sunday as the summer solstice marks the official start of astronomical summer in the Northern Hemisphere. The day will bring nearly 14 hours of daylight and signal the approach of the region’s hottest time.
The summer solstice will take place on 21 June at 08:25 GMT (12:25pm UAE time). This is when the Sun reaches its northernmost point in relation to Earth and stands directly above the Tropic of Cancer. It causes the longest day and shortest night of the year across the Northern Hemisphere.
According to Ibrahim Al Jarwan, Chairman of the Emirates Astronomical Society and a member of the Arab Union for Astronomy and Space Sciences, daylight hours in the UAE will reach around 13 hours and 50 minutes between 18 and 24 June. This makes it the brightest period of the year before daylight hours start to slowly decrease towards the autumnal equinox in September.
The solstice is an important point in Earth’s yearly journey around the Sun. Because Earth’s axis is tilted by around 23.5 degrees, the Northern Hemisphere gets its highest amount of sunlight, while the Southern Hemisphere sees its shortest day and the start of astronomical winter.
Al Jarwan said the Sun will be directly overhead at the Tropic of Cancer during the solstice. This means there will be almost no shadow at noon in places along the line of direct solar alignment. Across the Arabian Peninsula, midday shadows will be at their shortest point of the year.
Even though it brings the longest day, the solstice does not mean the hottest part of summer starts immediately. Temperatures usually keep rising in the following weeks as land and sea surfaces continue to absorb and hold heat.
Speaking about traditional Arab observations of seasonal change, Al Jarwan cited the saying, "There is no true heat until after the turning", referring to the period after the Sun begins its apparent southward movement and daylight hours gradually shorten. Historically, the strongest heat in the Gulf region happens during July and the first part of August.
During the first half of summer, from 21 June to around 10 August, average daytime temperatures in the UAE are expected to range between 41°C and 43°C. Overnight temperatures are forecast to stay between 27°C and 31°C.
This period is usually linked with the seasonal northerly and north-westerly winds known locally as the "Barah" winds, which can cause blowing dust and moving sand dunes.
Heatwaves may also develop, pushing temperatures at least three degrees above seasonal averages for several days in a row. In some places, daytime temperatures can go above 50°C during extended hot spells.
Hot and dry desert winds, known as "Samoom", may also affect parts of the country from time to time, making already harsh conditions even stronger.
The second half of summer, from around 11 August until the autumnal equinox on 23 September, is expected to bring higher humidity levels while temperatures stay high. Moist south-easterly winds, locally known as "Kous" winds, usually become more active during this time.
The extra moisture can help form convective clouds over the Hajar mountain range and nearby areas. This can sometimes lead to local thunderstorms and rainfall, which are common late-summer weather features in eastern parts of the country.
The date of the summer solstice can change slightly from year to year. It may fall on 20, 21 or 22 June depending on the calendar cycle and leap-year adjustments. The event happens because of Earth’s axial tilt, not because of any change in the distance between Earth and the Sun.
While astronomical summer begins on 21 June, meteorologists use a different definition based on temperature records. In the Northern Hemisphere, meteorological summer runs every year from 1 June to 31 August.
AI contributed to the creation of this article.