Cooler nights in UAE: September signals end of summer, start of autumn

Abu Dhabi: The National Center of Meteorology (NCM) has stressed that September marks the tail end of the UAE’s summer, with cooler nights and a gradual temperature decline expected in the latter half of the month.

Autumn will officially start on September 23, when the sun crosses the equator and appears to move south toward the Tropic of Capricorn.

Seasonal influences and wind patterns

The influence of the seasonal Indian monsoon low pressure weakens during September, though the UAE will continue to be affected by extensions of thermal lows from central Arabia. These can bring relatively active winds that stir up dust and sometimes reduce horizontal visibility.

Day-to-day winds typically shift from southeasterly in the late night and early morning to northwesterly by afternoon and evening due to land-sea breezes.

Rainfall and cloud formation

Conditions remain favourable for the formation of convective clouds, accompanied by rainfall, particularly in eastern regions, with some showers potentially reaching inland areas.

Rising humidity and fog

Humidity increases compared with August, averaging 49 percent. Fog or light fog is more likely in scattered parts of the country, especially in the second half of the month.

Temperature ranges

Average temperatures in September range from 32.3°C to 34.2°C, with highs between 38.5°C and 40.6°C and lows between 26.8°C and 29.3°C. The highest September temperature ever recorded was 51.1°C in Mukhairez in 2016, while the lowest was 16.5°C at Jebel Jais in 2015.

Wind speeds and extremes

Wind speeds average 11 km/h, though extremes can be much higher: gusts reached 92.2 km/h in Al Saa in 2023 and 109.3 km/h at Al Ain airport in 2008. Relative humidity typically peaks between 68 and 87 percent, with minimum levels between 17 and 29 percent.

Records for fog and rainfall

September 2014 saw the greatest number of foggy days, with 14 full days of fog and 12 of light fog. The heaviest September rainfall on record, 86.4 millimetres, was measured at Jebel Hafeet in 2006.