Astronomical autumn in the UAE will officially begin at 4:05 am on Wednesday, September 23, 2026, according to Ibrahim Al Jarwan, Chairman of the Emirates Astronomical Society and a member of the Arab Union for Astronomy and Space Sciences. The seasonal transition will bring a gradual fall in temperatures, while humidity and the likelihood of early-morning fog are expected to increase during the first half of autumn.
- Location: UAE
- Authority: Emirates Astronomical Society
- Autumn begins: September 23, 2026, at 4:05am
- Who is affected: Residents, commuters, farmers and outdoor businesses
- Seasonal impact: Gradually cooler conditions could support outdoor activities and tourism
- What’s next: Winter-type clouds are expected from mid-October, with rainfall chances increasing later in autumn
Autumn in the UAE will begin on September 23, 2026, at 4:05 am, marking the astronomical transition from summer to autumn. The timing was announced by Ibrahim Al Jarwan of the Emirates Astronomical Society. For residents, the change does not mean an immediate end to the UAE’s summer heat. Instead, temperatures are expected to fall gradually through the season, while humidity and early-morning fog become more noticeable before cooler weather settles in.
When does autumn officially begin in the UAE?
The UAE’s astronomical autumn begins with the September equinox, when the Sun is positioned directly over the equator before continuing its apparent movement towards the south.
According to Al Jarwan, the transition will take place at 4:05 am on September 23.
The equinox also marks a shift in the balance between daylight and darkness. While day and night are approximately equal around the equinox, nights will gradually become longer after it.
This is different from the meteorological definition of autumn, which begins on September 1 and is based on calendar months used for climate and weather analysis.
For residents, the practical change will be gradual rather than sudden. September can still bring high temperatures across the UAE, with cooler conditions developing as autumn progresses.
How much will UAE temperatures drop?
The temperature change is expected to become more noticeable as autumn moves towards November and December.
Based on the seasonal figures shared by Al Jarwan, average temperatures are expected to follow this pattern:
| Period | Average high | Average low |
|---|---|---|
| Start of autumn | 39°C | 26°C |
| Around early November | 31°C | 18°C |
| End of autumn | 25°C | 13°C |
This means the UAE could see average daytime highs fall by around 14°C between the beginning and end of astronomical autumn.
The shift is particularly relevant for Dubai residents and visitors planning outdoor activities. September will still feel like summer for much of the day, while November and December are expected to bring substantially more comfortable conditions.
The change also coincides with the UAE’s busiest period for outdoor events, attractions and seasonal tourism.
Why will humidity and fog increase?
The first half of autumn is expected to remain relatively humid, particularly during the night and early morning.
The combination of changing temperatures and moisture can create conditions favourable for fog and mist, particularly around dawn. This can be important for motorists travelling during early morning hours, especially in areas where visibility falls quickly.
The National Centre of Meteorology regularly issues weather updates and visibility warnings when fog or poor visibility is expected. Drivers should therefore check official forecasts before early morning journeys during the coming weeks.
For Dubai and other coastal areas, higher humidity can also make temperatures feel warmer than the actual reading suggests, meaning the transition to autumn may not immediately feel as cool as the calendar indicates.
When could rain and winter clouds arrive?
The seasonal transition will also gradually bring more winter-like weather patterns to the UAE.
Al Jarwan said winter clouds are expected to begin appearing around mid-October, with the possibility of rainfall increasing after the middle of autumn.
This should be viewed as a seasonal trend rather than a prediction of rain on a specific day. Daily weather conditions remain dependent on atmospheric systems monitored by the National Centre of Meteorology.
Recent UAE weather patterns have already included periods of humidity, fog and cloud development, showing some of the conditions that typically become more relevant as the country moves towards its cooler months.
The later part of autumn is generally when residents begin seeing more opportunities for pleasant outdoor weather, although conditions can still vary significantly from one day to another.
What does autumn mean for UAE residents and businesses?
The gradual temperature drop has practical implications across several parts of daily life.
For residents, cooler mornings and evenings will eventually make outdoor activities more comfortable. Parks, beaches, walking areas, outdoor dining venues and attractions typically become more appealing as temperatures ease.
The change is also significant for the UAE’s tourism and hospitality sectors, which enter a major outdoor season as temperatures become more manageable.
Farmers and gardeners also benefit from the seasonal transition. Al Jarwan described the first half of autumn as an important planting period across the Arabian Peninsula, when seedlings can be transplanted, saplings planted and autumn seeds sown.
For commuters, however, increased humidity and fog during the early morning hours mean visibility remains something to watch, particularly on major roads.
Why It Matters
The arrival of astronomical autumn signals the start of a gradual seasonal change across the UAE, rather than an immediate drop in summer temperatures.
Residents can expect September to remain warm, followed by increasingly comfortable conditions through October and November. Humidity and fog may become more relevant in the mornings, while winter-type clouds and greater rainfall potential are expected later in the season.
For outdoor businesses, tourism operators and residents planning activities, the changing weather will shape the UAE’s transition into its popular cooler months.
FAQs
When does autumn start in the UAE in 2026?
Astronomical autumn starts in the UAE at 4:05 am on September 23, 2026, according to Ibrahim Al Jarwan of the Emirates Astronomical Society.
Will the UAE become cooler immediately on September 23?
No. The temperature change will be gradual. Average highs are expected to decline from around 39°C at the start of autumn to around 31°C in early November.
When will UAE temperatures become more comfortable?
Temperatures are expected to become progressively more comfortable through October and November. By the end of astronomical autumn, average highs are expected to reach around 25°C.
Will there be more fog in the UAE during autumn?
Humidity is expected to increase during the first half of autumn, creating conditions that can support early-morning fog and mist.
When could rain become more likely in the UAE?
According to the seasonal outlook shared by Al Jarwan, winter-type clouds could start appearing around mid-October, with rainfall chances increasing after the middle of autumn. Specific rain events will depend on daily weather conditions and NCM forecasts.
The UAE’s astronomical autumn begins on September 23, bringing a gradual shift away from peak summer conditions. While September will remain hot, temperatures are expected to ease through November and December, with more comfortable outdoor weather, increased morning humidity and fog, and greater rainfall potential later in the season.
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