Some 54 mm of rain in a half hour ended days of up to 40-degree temperatures in Dong Nai. Residents were happy to escape the heat, but flooding provided other hazards.
Some streets were still flooded at 5 p.m., making rush hour traffic even worse as people traveled home from work.
A car stopped beside Tri An reservoir in Dong Nai to wait out the thunderstorm rather than risk driving through flooded city streets.
In Ho Chi Minh City, rain poured for more than half an hour starting at 4 p.m., flooding several roads in Binh Thanh District and Thu Duc City, causing chaos and congestion on major roads during rush hour.
A foreign woman rides a bicycle on Quoc Huong Street in Thu Duc's Thao Dien Ward, home to a large expat community.
The street was 20 cm underwater.
"The downpour came as a surprise and it caused us some trouble traveling around, but it let us cool off," said Van Huan (pictured), as he removes trash clogging a drain.
A woman walks through water above her ankles on Quoc Huong Street.
Le Dinh Quyet, a meteorologist from the Southern Meteorological Center, said low-pressure from the north caused rainfall of 10-20 mm across the city, causing temperatures to drop by 3-4 degrees Celsius.
But Quyet also said the city will likely suffer another heat wave in the coming days, and the rains will only become regular in mid-May.
