Winter chill returns as Bangkok cools; heavy rain, rough seas persist in south

SUNDAY, DECEMBER 14, 2025

New cold surge from China will cool upper Thailand, while northeast monsoon keeps heavy rain and rough seas in parts of South through December 16.

  • Temperatures in Bangkok and surrounding provinces are forecast to fall by 1–2°C due to a new high-pressure system from China.
  • The South will continue to experience persistent and heavy rainfall, affecting provinces such as Chumphon, Surat Thani, and Songkhla.
  • Seas in the Gulf of Thailand and the Andaman Sea will be rough, with waves reaching 2-3 meters or higher, prompting a warning for mariners and for small boats to stay ashore.

Weather “The chill is back” The Thai Meteorological Department’s (TMD) forecast for Sunday (December 14) says temperatures in Bangkok and surrounding provinces will fall by 1–2°C, with cooler mornings.

The North and Northeast will see more rain, with showers in 20% of areas.

24-hour forecast: The South will continue to see persistent rainfall, with heavy rain in some places, especially in Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala and Narathiwat, due to a strengthening northeast monsoon over the upper Gulf of Thailand, the upper South and the Andaman Sea.

Seas in the lower Gulf of Thailand will be fairly rough, while winds and waves across the Gulf of Thailand and the Andaman Sea will strengthen.

In the lower Gulf of Thailand, waves will be 2–3 metres, rising to over 3 metres in thunderstorms. In the upper Gulf of Thailand, waves will be around 2 metres, rising to over 2 metres in thunderstorms.

Winter chill returns as Bangkok cools; heavy rain, rough seas persist in south

In the Andaman Sea, waves will be 1–2 metres, with over 2 metres offshore and in thunderstorms.

Mariners in the Gulf of Thailand and the Andaman Sea are urged to navigate with caution and avoid stormy areas.

Small boats in the lower Gulf of Thailand should remain ashore during December 14–16.

For upper Thailand, the weather will turn colder, with rain and thunderstorms possible at first.

The Northeast will cool by 2–4°C with strong winds.

After that, the North, Central region, Bangkok and surrounding provinces, and the East will see temperatures fall by 1–2°C, as a new high-pressure system (cold air mass) from China spreads over the upper Northeast and the South China Sea, and is expected to cover upper Thailand on December 14.

People are advised to take care of their health due to changing conditions and cooler weather, while farmers should prepare to prevent potential damage to agricultural produce.

Winter chill returns as Bangkok cools; heavy rain, rough seas persist in south

The Thailand forecast from 6am on Sunday (December 14) to 6am on Monday (December 15).

Bangkok and the surrounding provinces

  • Cool in the morning, with light rain in some areas, and temperatures falling by 1–2°C.
  • Minimum temperature: 21–23°C
  • Maximum temperature: 30–32°C
  • Easterly winds: 10–20 km/h

North region

  • Cool in the morning, with showers/thunderstorms in 20% of areas, mainly in Phayao, Nan, Phrae, Uttaradit, Sukhothai and Phitsanulok, and temperatures falling by 1–2°C.
  • Minimum temperature: 17–21°C
  • Maximum temperature: 25–31°C
  • Mountain tops: cold to very cold, minimum 7–15°C
  • Northeasterly winds: 10–15 km/h

Northeast region

  • Cool in the morning, with showers/thunderstorms in 10% of areas, mainly in Loei, Nong Khai, Bueng Kan, Nong Bua Lamphu and Udon Thani, and temperatures falling by 2–4°C with strong winds.
  • Minimum temperature: 17–22°C
  • Maximum temperature: 27–33°C
  • Hilltops: cool to cold, minimum 12–18°C
  • Northeasterly winds: 10–30 km/h

Central region

  • Cool in the morning, with showers/thunderstorms in 10% of areas, mainly in Lopburi, Nakhon Sawan, Uthai Thani, Suphan Buri and Kanchanaburi, and temperatures falling by 1–2°C.
  • Minimum temperature: 19–22°C
  • Maximum temperature: 27–31°C
  • Northeasterly winds: 10–20 km/h

East region

  • Cool in the morning in the upper part of the region, with light rain in some areas, and temperatures falling by 1–2°C.
  • Minimum temperature: 22–24°C
  • Maximum temperature: 31–33°C
  • Northeasterly winds: 15–35 km/h
  • Sea waves around 1 metre, 1–2 metres offshore

South region (East Coast)

  • Thunderstorms in 60% of areas, with heavy rain in some places, especially in Chumphon, Surat Thani, Nakhon Si Thammarat, Phatthalung, Songkhla, Pattani, Yala and Narathiwat.
  • Minimum temperature: 19–24°C
  • Maximum temperature: 30–33°C
  • From Chumphon northwards: Northeasterly winds 15–35 km/h, waves 1–2 metres, over 2 metres in thunderstorms.
  • From Surat Thani southwards: Northeasterly winds 20–35 km/h, waves around 2 metres, over 2 metres in thunderstorms

South region (West Coast)

  • Thunderstorms in 60% of areas, mainly in Ranong, Phang Nga, Trang and Satun.
  • Minimum temperature: 22–25°C
  • Maximum temperature: 30–33°C
  • Northeasterly winds: 15–30 km/h
  • Sea waves around 1 metre, higher than 1 metre offshore, and over 2 metres in thunderstorms