Cold air mass keeps upper Thailand chilly; stronger winds expected

The Thai Meteorological Department’s forecast for Monday (January 5) says upper Thailand will remain cold, especially in the North and Northeast, with lows of 14°C.

Bangkok will be cool in the morning, while the South will continue to see rainfall.

Next 24 hours

The North and Northeast will be cool to cold.

The Central region, including Bangkok and the surrounding areas, the East, and the upper South will be cool in the morning, as a high-pressure system (cold air mass) from China continues to cover upper Thailand and the upper South.

People in these areas are advised to take care of their health due to the colder conditions and to be cautious about fire hazards due to dry weather.

The lower South will see less rain as the northeast monsoon over the Gulf of Thailand, the South, and the Andaman Sea remains moderate.

Seas in the Gulf of Thailand and the Andaman Sea will be moderate, with waves of around 2 metres in the lower Gulf, and 1–2 metres in the upper Gulf and the upper Andaman Sea.

In thunderstorm areas, waves may exceed 2 metres.

Mariners should proceed with caution and avoid sailing in thunderstorm areas.

People along the lower eastern coast of the South should also be cautious of waves breaking onto shore during this period.

Outlook January 6–10

Upper Thailand will remain cool to cold, with temperatures set to drop further and winds strengthening, as another relatively strong high-pressure system (cold air mass) from China extends over upper Thailand and the South China Sea.

The South will see more rainfall, with heavy rain in some areas of the lower South, as the moderate northeast monsoon over the Gulf of Thailand, the South, and the Andaman Sea strengthens.

Winds and waves over the Gulf of Thailand and the Andaman Sea will become stronger.

The lower Gulf will see waves of 2–3 metres, and over 3 metres in thunderstorm areas.

The upper Gulf will see waves of around 2 metres, and over 2 metres in thunderstorm areas.

Mariners in the Gulf of Thailand and the Andaman Sea should proceed with caution and avoid sailing in thunderstorm areas.

Small boats in the lower Gulf should remain ashore from January 6–9, 2026.

Forecast for Thailand from 6am Monday (January 5) to 6am Tuesday (January 6)

Bangkok and vicinity

• Cool in the morning
• Minimum temperature: 19–21°C
• Maximum temperature: 30–32°C
• Northeasterly wind: 10–20 km/h

North region

• Cool to cold with morning fog
• Minimum temperature: 14–17°C
• Maximum temperature: 29–31°C
• Mountain tops: cold to very cold; minimum temperature: 2–12°C
• Easterly wind: 10–20 km/h

Northeast region

• Cool to cold
• Minimum temperature: 14–17°C
• Maximum temperature: 29–32°C
• High elevations: cold; minimum temperature: 8–10°C
• Northeasterly wind: 10–20 km/h

Central region

• Cool in the morning
• Minimum temperature: 16–19°C
• Maximum temperature: 31–32°C
• Northeasterly wind: 10–20 km/h

East region

• Cool in the morning
• Minimum temperature: 18–21°C
• Maximum temperature: 30–33°C
• Northeasterly wind: 15–35 km/h
• Sea waves around 1 metre; offshore waves 1–2 metres

South region (East Coast)

• Upper South: cool in the morning
• Lower South: thunderstorms in 10% of the area, mainly in Surat Thani and Nakhon Si Thammarat
• Minimum temperature: 19–23°C
• Maximum temperature: 29–32°C
• From Surat Thani northwards: Northeasterly wind 15–35 km/h; waves 1–2 metres, around 2 metres in thunderstorm areas
• From Nakhon Si Thammarat southwards: Northeasterly wind 20–35 km/h; waves around 2 metres, over 2 metres in thunderstorm areas

South region (West Coast)

• Light rain in some areas
• Minimum temperature: 21–24°C
• Maximum temperature: 32–34°C
• From Phuket northwards: Northeasterly wind 20–35 km/h; waves 1–2 metres, offshore waves around 2 metres
• From Krabi southwards: Northeasterly wind 15–35 km/h; waves around 1 metre, offshore waves 1–2 metres