The UAE has officially entered astronomical autumn, but residents should not expect the summer heat to disappear overnight. The September equinox occurred early Wednesday, September 23, while the National Center of Meteorology (NCM) forecast continued high temperatures across the country, with some inland locations expected to reach 43°C to 45°C.
The equinox occurred at about 4:05am UAE time, marking the point when the Sun crosses the Earth’s equatorial plane as the Northern Hemisphere begins its transition towards winter. NASA explains that the September equinox is an astronomical marker rather than an instant change in local weather conditions.
That distinction helps explain why UAE residents can have an autumn date on the calendar while still experiencing temperatures more typical of late summer.
Where temperatures are highest
The strongest heat is expected away from the coast. According to the NCM forecast reported on Wednesday, inland parts of the UAE, including Al Ain and areas such as Liwa and Al Dhafra, are expected to see maximum temperatures in the 43°C–45°C range.
Coastal and island areas are forecast to be somewhat cooler, although temperatures remain high. Dubai, Sharjah, Ajman, Umm Al Quwain and Abu Dhabi are in the coastal and island range, while mountainous areas around the Hajar range and Jebel Jais are expected to be considerably milder.
The NCM outlook also points to relatively warm nights, with minimum temperatures varying significantly between coastal, inland and mountainous areas.
Why the equinox does not mean instant cooling
An equinox is an astronomical event. It marks a change in the relationship between Earth and the Sun, but it does not function like a switch that immediately changes the temperature.
NASA notes that the September equinox occurs when the Sun crosses the plane of Earth’s equator and the Northern and Southern hemispheres receive nearly equal amounts of sunlight. After the equinox, the Sun’s apparent path continues southward, bringing progressively shorter days to the Northern Hemisphere.
Temperature changes follow a different timetable. The land, atmosphere and surrounding seas retain heat, so the weather response to changing solar conditions develops gradually rather than at the exact moment of the equinox. NASA educational material also notes that oceans heat and cool slowly, creating a delay between astronomical seasonal changes and peak or minimum temperatures.
For the UAE, that means September 23 marks the astronomical beginning of autumn, but the more noticeable transition to milder conditions generally develops later.
Humidity and morning mist become more relevant
Heat is not the only feature of the current forecast. Humidity is expected to increase during the night and early morning, particularly in coastal and some inland areas.
The NCM outlook indicates a risk of mist in some western areas, while humid conditions are expected to continue as the week progresses. Winds are forecast to remain light to moderate, occasionally becoming stronger, while sea conditions remain slight.
These conditions can make early mornings feel different from the peak of summer, even while daytime temperatures remain high.
When will UAE weather start feeling more like autumn?
The shift is expected to be gradual rather than immediate. WAM, citing UAE astronomer Ibrahim Al Jarwan, reported that average maximum temperatures at the beginning of autumn are around 39°C, falling to about 31°C around the middle of the season and around 25°C towards its end. The same report said humidity rises during the first half of autumn and morning fog becomes more common.
The NCM’s near-term outlook similarly suggests that the UAE will remain warm after the equinox, with temperatures potentially edging higher on Thursday before a generally fair to partly cloudy pattern continues.
For residents, therefore, the message is straightforward: autumn has arrived astronomically, but the UAE’s familiar cooler season is still developing. The first noticeable changes are more likely to come through progressively cooler nights, changing humidity patterns and shorter daylight hours before daytime temperatures fall substantially.
What happened in the UAE on September 23, 2026?
The UAE entered astronomical autumn on September 23, with the equinox occurring at about 4:05am UAE time.
Why is the UAE still hot after the autumn equinox?
An equinox marks an astronomical change, not an immediate change in weather. Temperatures respond gradually to changing solar conditions and the heat retained by land, atmosphere and surrounding seas.
How hot will the UAE be on September 23?
NCM forecasts indicate highs of about 43°C–45°C in some inland areas, while coastal and mountainous locations are expected to be cooler.
Which UAE areas are expected to be hottest?
Al Ain and inland areas of Abu Dhabi emirate, including Liwa and Al Dhafra, are among the areas expected to see the highest temperatures.
Will UAE temperatures cool immediately after the equinox?
No. The seasonal transition is gradual, and near-term forecasts indicate that hot conditions will continue after September 23.
Will humidity increase in the UAE?
Yes. The forecast indicates higher overnight humidity, with mist possible in some western areas and fog or mist risk potentially becoming more widespread as the week progresses.
When does UAE weather normally become cooler?
Cooling develops progressively during autumn. WAM reported average maximum temperatures of about 39°C at the start of autumn, around 31°C in the middle of the season and about 25°C towards its end.
