Astronomical calculations indicate that autumn in the UAE will begin at 4:05am on Wednesday, September 23, bringing a gradual decline in temperatures.

Ibrahim Al Jarwan, Chairman of the Emirates Astronomy Society and a member of the Arab Union for Astronomy and Space Sciences, said the constellations Gemini, Taurus and Leo, along with Sirius, Suhail and the Pleiades star cluster, will be visible in the eastern sky at dawn as autumn begins.

He said winter clouds would begin to appear from mid-October, with the likelihood of rainfall increasing during the second half of autumn.

How far will temperatures fall in the UAE?

Astronomical forecasts indicate that temperatures will gradually decline throughout autumn.

Start of autumn: Maximum temperatures will be around 39°C, with minimums of 26°C.

Mid-autumn, in early November: Maximum temperatures will fall to around 31°C, while minimums will reach 18°C.

End of autumn: Maximum temperatures are forecast at around 25°C, with minimums of 13°C. These conditions will coincide with the winter solstice on December 22.

Humidity is also expected to increase during the first half of autumn, creating conditions favourable for early-morning fog.

Autumn equinox and changing day length

Al Jarwan told the Emirates News Agency, WAM, that the first half of autumn is considered the best time to plant crops across the Arabian Peninsula. During this period, farmers transplant seedlings, plant saplings and sow seeds for the autumn growing season.

The autumn equinox occurs when the sun is directly above the equator and continues its apparent movement southwards. At this point, day and night are nearly equal in length.

About a week after the autumn equinox, nights gradually become longer and daylight hours begin to decrease.

At the start of the season, the length of shadows cast by objects at noon in the UAE will be about half their height, before gradually increasing.