Summer storms will bring downpours to parts of the Northeast, Central, East and South over the next few days as a low-pressure system moves over the upper part of the country, the Meteorological Department warned on Monday.
The low-pressure front, which will be active until March 7, combined with a strong, south-southeasterly wind will bring overcast conditions and cause temperatures to hover around 38-40 degrees Celsius.
The front will cause weather changes all the way to the South, with the department warning of possible showers and waves of up to one metre in both the Gulf of Thailand and the Andaman Sea.
Between March 8-9, a cold front from China will move towards the region, causing storms as it clashes with the prevailing low-pressure, warm front across the country.
Those living in the North and the Northeast should expect stormy conditions with heavy rain and lightning strikes during the period.
Waves of 1-2 metres are expected across the South.
Separately, satellite images and data from the Geo-Informatics and Space Technology Agency (Gistda) showed that as of 8am on Monday, five provinces had extremely high levels of ultra-fine PM2.5 pollutants - far above the safe threshold for exposure over a 24-hour period of 37.5 microgrammes per cubic metre set by the government.
Nakhon Phanom reported the worst fine dust pollution, with PM2.5 levels averaging 82.8 µg/m³, followed by Mukdahan (82.5µg/m³), Kalasin (76.5µg/m³), Phayao (76µg/m³), and Roi Et (75.6µg/m³).
Thirty-one provinces reported unhealthy levels of fine dust pollution.
Bangkok, meanwhile, has enjoyed reasonably good air quality over the past several days, according to Gistda. Satellite images taken on Sunday showed 1,015 fire hotspots across the country, 355 of them in forest reserves.
Myanmar had the most hotspots in the region with 3,963, followed by Cambodia (1,686), Laos (1,030), and Vietnam (335).
Due to a fire across the border, Preah Vihear (Phra Viharn) National Park in Sri Sa Ket’s Kantharalak district, on the border with Camboldia, will remain closed until March 8.
Park chief Jit Ardsanjorn said that the smoke from the fire affected several areas in Thailand, especially around Noen Nub Dao on the eastern slopes of Pha Mo E Daeng.
Park officials and officers from Preah Vihear Forest Fire Control Station and soldiers were helping control the blaze, making more firebreaks.
Extra firetrucks and crews were on standby if needed, Ms Jit said.