Education authorities said schools will stay closed tomorrow as more thundery weather is forecast.
Flights at Abu Dhabi airport resumed today afternoon after being suspended for several hours, and Dubai International also experienced delays, aviation authorities said.
The rains disrupted the Abu Dhabi Air Expo held at the capital's Al-Bateen airport.
Abu Dhabi's stock market said it suspended trading and cancelled all morning deals after many traders could not reach the bourse.
Others showed shades and construction barriers that had collapsed on cars.
In Dubai, police registered more than 250 road accidents by midday, local media reported.
The weather agency in the UAE, which ranks among the world's 10 driest countries, said more rain is expected on tomorrow.
The country's annual rainfall stands at 78 millimetres (three inches), more than 15 times less than the amount for an average year in Britain.
But the National Centre for Meteorology and Seismology said some 240 millimetres of rainfall was recorded today near Al-Ain.
"Not #london or #dublin, this is Dubai today after heavy rain!" wrote Andrea Colonnelli on Twitter posting a video of cars wading through a flooded street.
Another video posted on the micro-blogging site showed a man kayaking through a flooded residential area.
"2 days of rain in #Dubai, my neighbour is kayaking," read one comment.
