June 21 Marks the Astronomical Start of Summer

The official start of summer is set for June 21, marked by the summer solstice at precisely 02:42 UTC (06:42 UAE time). This season will last three months until around September 23, when the autumnal equinox occurs.
Ibrahim Al Jarwan, Chair of the Emirates Astronomy Society and a member of the Arab Union for Astronomy and Space Sciences, stated that on the summer solstice, the sun aligns directly over the Tropic of Cancer. This alignment results in noontime shadows disappearing in the southern parts of the UAE, minimal shadow length across the Arabian Peninsula, and the shortest shadow length in the northern hemisphere. Consequently, the longest daylight period and shortest night occur in this hemisphere. Between June 18 and 24, the UAE experiences the year's longest day, lasting up to 13 hours and 43 minutes.
Rising Temperatures
During the first half of summer, from June 21 to August 10, temperatures are expected to rise, averaging between 41°C and 43°C during the day and 26°C to 29°C at night with generally dry conditions and increased wind activity. The "Barih" summer winds prevail, bringing north and northwesterly winds that stir sand dunes and occasionally raise dust levels. Hot airwaves may cause temperatures to soar at least 3 degrees above normal for a period of two consecutive days, and sometimes up to six days or more, with some areas surpassing 50°C during the day, along with the occurrence of hot and dry "Simoom" winds.
In the latter half of summer, which spans from August 11 to the autumnal equinox on September 23, high humidity levels combine with ongoing heat, leading to "Kos" winds that promote the development of cumulus clouds over the Hajar Mountains and adjoining areas, often resulting in thunderstorms known locally as "Al Rawaih."