Bangkok and popular tourist provinces in the eastern and southern parts of the country are braced for more rain in the days to come.
The Meteorological Department warned people in Greater Bangkok that the latest forecast for rain shows it will cover 70% of the capital until next Tuesday.
Downpours in some areas in the capital on Tuesday night and Wednesday morning clogged traffic during rush hours, with the Lat Phrao area among the worst.
Heavy rains are expected until the coming weekend in Andaman coastal provinces from Ranong to Phangnga, Phuket, Krabi, Trang and Satun, the Southern Meteorological Centre said. The centre advised small boats not leave shore due to possible rough seas during this period.
With rains spreading to the eastern province, Trat governor Phayakkaphun Phokaew directed officials to stay alert for possible abrupt flooding. Hotel and resort operators on Koh Kood and Koh Chang have been advised to warn tourists not to go swimming due to possible rip currents, he added.
The Disaster Prevention and Mitigation Department has issued a warning against flooding, storms and landslides in 20 provinces in the Central, East and South regions until Sunday.
Under the warning, all six disaster relief centres and the department's offices in the 20 provinces are to take measures to cope with flooding, storms and landslides as a result of heavy rainfall and strong waves during that period.
The 20 provinces are Bangkok, Kanchanaburi, Nakhon Pathom, Prachuap Khiri Khan, Pathum Thani, Nonthaburi, Phetchaburi, Ratchaburi and Samut Prakan in the Central region; Sa Kaeo, Chon Buri, Chanthaburi, Rayong, Trat and Prachin Buri in the East; and, Ranong, Phangnga, Krabi, Phuket and Trang in the South.