Much of the country woke up to heavy fog early on Tuesday morning, with authorities urging drivers to exercise caution on the roads.
Humidity edged close to 90 per cent at 6.30am. High summer temperatures remain and the National Centre of Meteorology has forecast highs of 45°C in some areas.
In Abu Dhabi, police called on drivers to be cautious on the roads and to look for temporary speed reductions, which are displayed on motorway boards.
In poor weather, the speed limit is often cut from 120 kilometres an hour to 80kph.
There was heavy fog at Abu Dhabi airport early on Tuesday, but the display board showed flights were departing as scheduled as of 6am.
Humid conditions are forecast to continue throughout the week after a cooler than expected start to September — called Sweat-tember by many residents.
After a dry summer, September is typically the most humid month, which is a consequence of changing weather patterns.