More heavy rain was forecast to continue in 43 provinces, covering all regions, on Tuesday, with flood warnings.
The Meteorological Department said the active monsoon trough lies across the North and upper Northeast of Thailand and into a tropical depression over the upper South China Sea.
Meanwhile, a rather strong southwest monsoon prevails across the Andaman Sea and the Gulf of Thailand.
With these conditons, heavy rain was expected to continue in parts of the North, the Northeast, the Central Plains, the East and the South on Tuesday. The weather office warned of possible flash floods and water courses overflowing.
Affected areas are 11 provinces in the North, 18 provinces in the Northeast, five in the Central Plains and seven in the East.
Waves up to 2-3 metres high were expected in the upper Andaman Sea and, more than 3 metres high during thundershowers. Waves of about 2 metres were likely in the upper Gulf of Thailand, and more than 2 metres high during thundershowers. All boats should proceed with caution and small boats should stay ashore, the department said.
