September humidity brings fog back to UAE roads as alert issued for coastal and inland areas

September humidity brings fog back to UAE roads as alert issued for coastal and inland areas

The National Centre of Meteorology issued a fog alert for the early hours of September 2, 2026, warning drivers of reduced horizontal visibility in coastal and internal areas from 1am to 8:30am. The alert marks the start of a seasonal pattern that will dominate UAE weather conditions through the coming months.

Relative humidity is climbing to around 90 per cent overnight in both coastal and inland areas as September opens, creating conditions for fog or mist formation over coastal and internal stretches during the night and into early morning. On Wednesday, the NCM forecasts fair to partly cloudy skies, with convective clouds possible over eastern areas by afternoon and daytime highs still reaching the low to mid 40s inland.

Khalifa University research indicates that fog events in the UAE have become more frequent and last longer since the 1980s. Fog season occurs most frequently between September and March, peaking in December and January. Despite being a desert country, the UAE experiences up to 50 foggy nights per year.

How desert fog forms

Warm, moisture laden air moves inland from the Arabian Gulf and the Arabian Sea during the evening. After sunset, the desert surface loses heat quickly through radiative cooling, and the air just above the ground cools along with it. Once that air becomes saturated, water vapour condenses into countless tiny droplets suspended near the surface. Meteorologists call this radiation fog, and it accounts for around 95 per cent of all fog recorded in the UAE.

Wind speed matters. Research based on data from Abu Dhabi International Airport shows that a light breeze of roughly five knots helps fog form and settle. Anything stronger tends to break it apart before it can thicken.

Fine sand and dust particles suspended in the atmosphere act as condensation nuclei, giving water vapour something to cling to as it turns into droplets. Without that dust load, much of the country's fog simply would not form.

Emirati astronomer Ibrahim Al Jarwan, Chairman of the Emirates Astronomy Society, has linked the current spell to the seasonal calendar. He noted that August and September typically bring high humidity levels as the peak summer season winds down.

The UAE entered what is known as Suhail season on August 24, a date tied to the star Canopus becoming visible before dawn. Canopus is the second brightest star in the night sky after Sirius, located approximately 310 light years from Earth in the constellation Carina, and is visible about 40 minutes before sunrise on the south eastern horizon. The star's appearance traditionally marks the beginning of Al Safriya season, a period regarded as the first of the milder seasons when beneficial rainfall is anticipated, with winter traditionally beginning around 100 days after Suhail's appearance.

Humidity and the dew point

Every NCM bulletin during fog season centres on one figure: relative humidity. Humidity, and specifically how close the air temperature sits to the dew point, decides whether a given night produces fog.

Dew point is the temperature at which air becomes fully saturated with moisture. When the overnight air temperature drops down to meet the dew point, water vapour begins condensing into droplets. The narrower that gap, the more likely fog becomes.

In early September, the Arabian Gulf is still carrying the heat of a full summer, so evaporation keeps pumping moisture into the lower atmosphere. Sea breezes carry that humid air inland through the day. Once night falls and winds turn calm, the desert floor sheds its heat rapidly and the air temperature slides toward a dew point that is already sitting high. When the two meet, fog forms.

Geographic concentration zones

Fog does not spread evenly across the UAE. It tends to concentrate in specific pockets, largely dictated by geography.

Researchers at Khalifa University's Environmental and Geophysical Sciences Lab have identified the Sweihan desert and the areas southwest of Abu Dhabi as two of the country's primary fog formation zones, a result of how quickly open desert surfaces lose heat overnight. Fog typically builds first in these areas before expanding outward. Most fog is recorded between 20 and 100 kilometres inland.

According to NCM data, four of the five foggiest roads in the UAE are in Abu Dhabi: Al Ghwaifat, Suwaihan, Al Ajban, and the road to Madinat Zayed in Al Dhafra. In Dubai, the Dubai to Al Ain Road is the primary fog affected area, where visibility has been reported below 500 metres.

Historical NCM records show that in one such event, fog extended across Sweihan in Al Ain, Al Fayah in Abu Dhabi, Madinat Zayed, Ghayathi and Liwa in the Al Dhafra region, along the Abu Dhabi to Al Ain and Al Ain to Dubai roads, at Al Maktoum International Airport, on the Ghantoot road, and across Jebel Ali, Al Minhad and Saih Al Salam in Dubai, as well as the Mleiha road, Sheikh Mohamed bin Zayed Road and Emirates Road in Sharjah.

Al Dhafra in particular appears repeatedly in NCM alerts, with fog reported forming across its coastal and western stretches on multiple occasions, prompting red and yellow warnings.

The human cost of low visibility

The consequences of driving through thick fog can be severe. On March 14, 2019, dense fog led to 68 vehicle collisions in separate incidents across the UAE, resulting in one fatality and multiple injuries, with visibility dropping to 200 metres. On a single foggy morning in December 2016, Dubai experienced 119 car crashes between 4am and 9am, with police receiving more than 1,980 calls for assistance by noon.

Official response and alert systems

The response from UAE authorities is fast and, in parts, automated. The NCM's alert system uses a colour coded scale. A yellow alert calls for awareness and careful driving, orange signals a need for higher preparedness, and red marks conditions of extreme danger.

These alerts are pushed directly to residents' phones through the National Early Warning System, which uses location based cell broadcast technology to deliver immediate safety messages directly to mobile devices within targeted geographic areas, bypassing network congestion and displaying as priority pop ups with loud audible tones. The National Emergency Crisis and Disaster Management Authority operates under the National Supreme Security Council and works in coordination with multiple federal and local partners including the NCM, Ministry of Interior, and emirate level police forces to issue alerts based on geographic location and the nature and extent of the hazard.

Traffic authorities across the emirates mirror this response. During dense fog mornings, Abu Dhabi Police, Dubai Police, Dubai's Roads and Transport Authority, and Sharjah Police issue public advisories, urging drivers to expect delays, switch on headlights, and avoid sudden lane changes in low visibility. Abu Dhabi Police also activate a speed reduction system during foggy weather as a preventive measure, reducing limits to 80km/hr in affected areas to reduce road accidents.

NCM safety guidance

The National Centre of Meteorology maintains a standing set of safety messages for periods of thick fog. The core guidance includes the following.

Stay alert to changing conditions by following official weather bulletins and licensed media rather than relying on habit or memory of a familiar route. Exercise the utmost care while driving in areas of poor visibility, and follow any instructions issued for fog affected roads in the early morning. If conditions make driving impossible, it is best to stop the vehicle off the road, clear of moving traffic, rather than attempting to continue.

Leave a generous gap between your vehicle and the one ahead. Reduce speed on entering a foggy stretch, and avoid overtaking the vehicle in front unless it is genuinely necessary. Keep out of the leftmost lane, which is designated for traffic moving at the posted speed limit. If you must stop, do not do so on the shoulder of the road, but move to a genuinely safe location away from traffic and activate your hazard lights there. Reserve hazard lights for emergencies and otherwise rely on low beam headlights.

Concentrate solely on the road ahead, and use ground markings as a guide through reduced visibility. Do not accelerate back to normal speed the moment fog appears to clear, since conditions can return without warning. Parents are advised to delay outdoor trips with children during periods of bad weather, and drivers are reminded to stay informed of local conditions and avoid using their phones altogether while driving through fog.

What the rest of September holds

Forecasts through late August and into the first days of September have followed a consistent structure: hot, largely fair days with convective cloud building over eastern and southern areas by afternoon and an occasional chance of rain, followed by rising humidity after dark and a renewed chance of fog or mist forming somewhere along the coast or inland before sunrise.

The NCM expects temperatures to ease gradually as the month progresses, but that is precisely the condition under which fog tends to increase rather than fade. Cooler nights settling over ground still holding the moisture of a full summer close the gap to the dew point more quickly, not less.

For anyone regularly using the Abu Dhabi to Dubai or Abu Dhabi to Al Ain routes, the sensible habit for the coming weeks is straightforward. Check the NCM's forecast before setting out early, and build a little extra time into any journey that begins before 9am.