Bangkok and five vicinity provinces faced two fronts of discomfort on Thursday: hot weather and haze.
The Thai Meteorological Department said the capital city would have the country's highest temperature of 38 degrees Celsius, while the Pollution Control Department (PCD)'s daily update cited 35 areas with levels of particulates smaller than 2.5 microns (PM2.5) beyond safe limits.
The weather bureau said that the high pressure area over upper Thailand was weakening, while the southeasterly wind brought the moisture from the South China Sea to upper Thailand where people would experience the increase in temperature during the daytime. The northeast monsoon over the Gulf and the South was also weakening causing less rain over the South.
Greater Bangkok from 6am on Thursday to 6am on Friday can expect a maximum temperature of 36-38C, while the North and Northeast will see 34-37C and the South 31-36C.
The PCD report said that 35 areas of Greater Bangkok had 51-73 micrograms of PM2.5 per cubic metre of air - rising beyond the safe limit of 50 micrograms - due to the lack of wind and the influence from the high pressure area over upper Thailand.
The peak levels were in the Rama II roadside spot in Bangkok's Bang Kho Laem district at 73 micrograms; the Sathorn district's Khlong Toei area at 64 micrograms and at Wat Thung Don area at 65 micrgrams; the Din Daeng district at 67 micrograms; and the Samut Prakan's Phra Pradaeng district at 65 micrograms.
The PCD also reported that the North had lower PM2.5 levels in all areas but still at unsafe levels such as tambon Sri Phum of Chiang Mai's Muang district with 52 micrograms.