UAE summer to end soon: Autumn equinox to begin this month, rainfall expected

[Editor's note: This article is being reshared as autumn equinox starts today, September 22]

Residents across the UAE can look forward to the end of summer as September marks the final month of the season. Nighttime temperatures will gradually decrease, with a more noticeable drop expected in the latter half of the month.

The autumn equinox will start on September 22 at 4.44pm local time, when the Sun will be directly proportional to the equator, with northern and southern hemispheres seeing equal amount of rays.

Ibrahim Al Jarwan, board chairman of the Emirates Astronomical Society and a member of the Arab Union for Astronomy and Space Sciences, highlighted that following the autumn equinox, day and night will be of equal length in the UAE. From this point forward, nights will gradually become longer than days as we move towards winter.

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In contrast, polar regions experience a much more extreme shift. During this period, the Arctic Circle transitions from continuous daylight to a prolonged period of darkness, while the Antarctic Circle begins to emerge from its extended night, with the sun rising again after several months of darkness.

He also noted that early autumn evenings will reveal several prominent star constellations. Notable among them are the Big Dipper and the Great Square of Pegasus, also known as the Aquarius Square in Arab astronomy, which will become visible in the eastern sky. The peak of the following meteor showers will occur in autumn: Orionids from October 20-22, Leonids from November 16-18, and Geminids from December 13-15.

According to Al Jarwan, starting from the autumnal equinox, temperatures are expected to drop below 25°C at night and below 40°C during the day, marking the beginning of milder weather. Night-time cooling will become noticeable when temperatures fall below 20°C, which typically happens from mid-October to mid-April. Daytime cooling, on the other hand, will start when temperatures fall below 30°C, usually occurring from mid-November to mid-March.

Additionally, the winter rainy season will start in early November and continue through the end of March. During this period, approximately 22 per cent of the year’s total rainfall will occur, with the latter half of autumn seeing the most significant precipitation. High humidity levels during this time will contribute to the formation of morning fog and dew, particularly from mid-September to mid-November.

Rainfall expected

During the month of September, residents can expect rain and thunder in some parts of the country, as per a forecast by the National Centre of Meteorology. This is a result of expected cumulonimbus cloud formation in eastern areas. This may also extend to internal regions, causing rain at different intensities.

There is also a forecast of fresh winds, sometimes blowing with dust, causing poor visibility. This is an effect of the Indian monsoon depression gradually weakening, and the desert thermal lows over the Arabian Peninsula.

Humidity is set to rise in comparison to the month of August, especially during the second half of the month. The chance of fog and mist formation will increase in some parts of the country, with relative humidity resting at 49 per cent.

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