Bangkok is expected to experience its coolest weather in almost 40 years on Sunday and Monday, with low temperatures of 16 degrees Celsius, while lows in the North and the Northeast will be 12°C, forecasters said on Thursday.

Temperatures are expected to drop as low as 12°C in 13 provinces in the North (Mae Hong Son, Chiang Mai, Lamphun, Lampang, Nan, Phrae, Tak, Sukhothai, Phitsanulok, Phetchabun, Kamphaeng Phet, Phitchit and Nakhon Sawan); and six provinces in the Northeast (Loei, Nong Khai, Beung Kan, Udon Thani, Nong Bua Lam Phu and Nakhon Ratchasima)

Average lows in Bangkok and surrounding provinces are expected to be around 21°C, but on Sunday and Monday they will drop to 16°C, the coolest weather in almost 40 years, the director of the Centre for Climate Change and Disaster at Rangsit University said.

Bangkok people may not experience such cool weather in the future given the global warming trend, but they must be careful as the cool season brings with it harmful dust pollution from burning and other sources, he said.

The Meteorological Department on Thursday said temperatures are expected to drop by 5 to 7C in the North and the Northeast and by 2 to 5°C in Bangkok and surrounding provinces between Jan 10 and 13.

The northeast monsoon over the Gulf and the South will strengthen with more rains and heavy rain in the lower South.

Waves in the Gulf are forecast to be 2 to 4 metres high and above 4 metres during thundershowers. Waves in the Andaman Sea are likely to be above 3 metres high during thundershowers.