The National Centre of Meteorology on Thursday issued a fog alert for all of the Abu Dhabi emirate, plus parts of Dubai and Ras Al Khaimah.
Abu Dhabi Police lowered the speed limit on many roads.
The poor weather for driving is expected to improve later this morning, leaving a mainly sunny day which will be cloudy at times.
The traffic rule, introduced in Abu Dhabi in 2019, means speed limits are capped whenever visibility is poor.
The morning fog is expected to last throughout the weekend over some coastal and inland areas, especially in the west of the country.
From Friday to Sunday, nights will be humid, with fog in the early mornings.
Temperatures will reach the mid to high 30s during the day but could go as low as 17C at night in some areas, the weather centre's forecast showed.
The high humidity in early October should drop off later in the month, giving way to several months of cool and sunny winter conditions.
