Thailand is officially entering its cold season on Saturday but the southern region is will remain battered by rain at least until Friday. The Meteorological Department on Wednesday announced that Saturday will mark the official start of cold season, which will continue until mid-February. Temperatures will drop sharply in the second half of December and remain cool to the end of January, it added. Rainfall will subside in most parts of the country through the coming weekend, with downpours expected in Prachuap Khirikhan and all southern provinces until Friday, the weather agency said. Forecaster Prapaporn Wongsaming warned of heavy rain and possible flash floods in all six provinces on the Andaman coast -- Ranong, Phangnga, Phuket, Krabi, Trang and Satun -- on Friday.