Heavy fog covered most of the country and is not expected to lift until late morning.
The National Centre for Meteorology and Seismology said visibility is down to less than 1000 metres.
Fog formed over Abu Dhabi, Dubai, Al Ain, Ras Al Khaimah, said the centre.
UAE forecaster urged residents to be on alert and comply with travel advice issued by authorities.
Meanwhile, the weather is forecast to be fair and hazy for the rest of the day, with south-westerly winds blowing gusts between 12-22kph across interior regions and could reach 28kph.
Humidity levels are expected to rise overnight and early morning over most coastal and internal areas, with more chances of fog formation. Humidity levels are set to be around 95 per cent on Friday along parts of the UAE’s coast.
Temperatures are expected to rang through the day between 14°C and 35°C inland, 16°C to 32°C along the coast, and 11°C to 23°C in the mountains.