September 21 is the official last day of summer in the UAE.
According to Ibrahim Al Jarwan of the Arab Union for Astronomy and Space Sciences said that autumn will begin on September 22, 2020, at 5:31 PM.
Talking on Sharjah News, Al Jarwan explained that the sun will be directly over the equator, and will start evolving towards the southern hemisphere.
In effect, day and night will be of equal length that day, following which days will get shorter and nights longer.
The day and night will be of equal again starting March 20, 2021.