After the warning of an immanent low-pressure storm, the Petroleum Thai Cooperation Friday sent a vessel to remove 115 workers from the oil rig and ferry them to Songkhla.
The southern provinces can expect over a hundred millimetres of rain, gusty winds and high seas, the acting director of the East Coast Meteorological Centre Phayao Muangngam said.
The eight provinces are Narathiwat, Pattani, Yala, Songkhla, Phattalung, Nakhon Si Thammarat, Satun and Trang.
Phayao said that the low-pressure system would not develop into a tropical storm or a typhoon because of conditions in the Gulf of Thailand. But rain lasting five hours in some places would cause downtown flooding and possible landslides around mountain areas.
Local authorities in Narathiwat and Songkhla had established teams to monitor the situation, she said.