The Meteorological Department has warned of a sharp temperature drop across Thailand’s upper regions between November 17 and 23, with the Northeast expected to face the most dramatic plunge of 4–7°C.
Temperatures in the Central region, including Greater Bangkok, as well as the North and East, are forecast to fall by 2–4°C during the same period.
The advisory follows Sunday morning’s reading of 6°C at Doi Inthanon, the nation’s highest peak, marking the lowest temperature recorded so far this cool season.
According to Sukanyanee Yawiyacharn, director-general of the Meteorological Department, a strong cold air mass from China is now spreading across upper Thailand and the South China Sea, setting off unstable conditions as outlined in Announcement No. 3.
In the initial phase of the shift, isolated thunderstorms are expected to form over the Northeast, particularly in Ubon Ratchathani, Si Sa Ket, Surin, Buri Ram and Nakhon Ratchasima, before temperatures drop sharply and strong winds arrive. Similar weather patterns will extend to other regions soon after.
Authorities are urging residents to brace for the sudden chill, especially vulnerable groups such as the elderly, young children and individuals with health conditions.
The department also cautioned that dry air and strong winds could increase the risk of fires, advising farmers to prepare for potential impacts on their crops.
Meanwhile, the South is expected to see increased rainfall and rough seas in both the Gulf of Thailand and the Andaman Sea.
Heavy to very heavy rain is likely in parts of the southern provinces, driven by a strengthening northeast monsoon and an easterly wind surge pushing into the region.
Sea conditions in the Gulf are forecast to produce waves of 2–3 metres, while the upper Andaman will see 2-metre waves, rising above 3 metres during thunderstorms.
Residents along the east coast are advised to remain alert for flash floods, runoff and strong coastal waves, particularly in foothill areas, waterways and low-lying zones.
Mariners in both the Gulf and the Andaman are urged to proceed with extreme caution and avoid storm-affected waters. Small boats in the Gulf are advised to stay ashore from November 19–23.
