The Meteorological Department on Sunday warned people living in the East and Lower Northeast to be mindful of rain-related dangers.
Heavy rain has been forecast in those regions through September 29.
Bangkok and adjacent provinces were expecting rain to fall on 40 per cent of the area on Sunday.
The weather bureau also issued a warning to fishermen in the Andaman Sea, saying waves could reach two metres in height from September 27 to 29.
People planning to travel to Taiwan between September 28 and 30 were advised to closely monitor weather updates because Typhoon Trami was on its way.
“The typhoon will have no impact on Thailand but could affect travellers to Taiwan,” the bureau said.