Why does the UAE get so foggy every summer? The science behind the seasonal phenomenon

Dubai: Every summer, particularly in the early morning hours, thick fog blankets some roads across parts of the UAE, reducing visibility and disrupting travel. 

While fog is often associated with cold weather, experts say the phenomenon is common during the UAE's hottest months because of a unique combination of humidity, desert conditions and overnight cooling.

Fog is essentially a cloud that forms at ground level when water vapour condenses around microscopic particles such as dust. It can range from light mist to dense fog, reducing visibility to less than one kilometre and, in severe cases, to only a few metres.

Despite its arid climate, the UAE experiences ideal conditions for fog formation during summer. Warm, moisture-laden air from the Arabian Gulf and the Arabian Sea moves inland during the evening, bringing high levels of humidity.

As the desert rapidly loses heat after sunset through a process known as radiative cooling, the air closest to the ground cools with it. When the air cools enough to become saturated, water vapour condenses into countless tiny droplets suspended near the surface, forming what meteorologists call radiation fog.

According to Ibrahim Al Jarwan, Chairman of the Emirates Astronomy Society and a member of the Arab Union for Astronomy and Space Sciences, this type of fog becomes increasingly common during the second half of summer, particularly in August, when humid air masses become more frequent over the UAE. Even a slight overnight drop in temperature can be enough to trigger dense fog once the air becomes saturated.

Another important factor is the dew point, the temperature at which air becomes saturated with moisture. When the overnight air temperature falls to the dew point, water vapour begins condensing into tiny droplets, allowing fog to form. The closer the air temperature is to the dew point, the greater the likelihood of fog developing.

The UAE's geography also plays an important role. Although it is a desert country, its proximity to the warm Arabian Gulf provides a constant source of moisture. During the evening, sea breezes transport this humid air inland, where it mixes with dust and fine sand particles suspended in the atmosphere. These particles act as condensation nuclei, allowing water droplets to form more easily and increasing the likelihood of fog.

Because these conditions occur regularly, the UAE can experience around 50 fog days each year, despite being one of the world's hottest countries.

The phenomenon frequently disrupts road, air and maritime transport, particularly between June and September, prompting weather alerts from the National Centre of Meteorology.

Dense fog can develop rapidly before sunrise, making it difficult for motorists to judge speed, distance and road conditions, significantly increasing the risk of traffic accidents.

The UAE usually advises drivers to monitor weather forecasts before travelling, reduce speed when visibility deteriorates, maintain greater distances between vehicles and use low-beam headlights rather than high beams, which reflect off the fog and further reduce visibility. If conditions become too dangerous, motorists are urged to pull over safely away from moving traffic until visibility improves.

Fog can also affect health, especially among people with asthma, chronic respiratory illnesses or cardiovascular disease. Prolonged exposure to cool, damp air may irritate the airways and worsen breathing difficulties, while older adults and vulnerable individuals may experience additional strain on the heart during cool, humid mornings.