The Thai Meteorological Department (TMD) on Friday urged citizens to beware of the heat, especially vulnerable groups, as the weather is expected to remain hot and sunny until early May.
TMD director-general Chomparee Chompurat said the temperatures in Thailand will remain high this summer, with the mercury tipped to climb to 43C in the North and Northeast, while the Central Plains region and the East will see similar temperatures of up to 42C.
The top four provinces to feel the heat will be Sukhothai, Tak, Lampang and Mae Hong Son.
Ms Chomparee warned elderly and obese people to avoid working or exercising outdoors during this period to avoid any risk of heat stroke.
Nathapon Suttisuntharin, director of the Institute of Geriatric Medicine, said people who subject themselves to these conditions could see their body temperature exceed 40.5C, potentially leading to dizziness, slow reflexes and even seizures.
To minimise the risk of heatstroke for the elderly, he urged them to stay indoors in well-ventilated areas if possible, stay hydrated and take regular cold showers.
Anyone showing signs of heatstroke should immediately be placed on their back with clothes loosened in a ventilated room.
Dr Thongchai Keeratihattayakorn, director-general of the Department of Medical Services (DMS), said people are unlikely to perish but it pays to take precautions as symptoms can be alarming and require care.
Dr Thanaboon Worakijthamrongchai, a neurologist at the Neurological Institute of Thailand, said most fatalities linked to heatstroke tended to have a comorbidity such as heart disease or hypertension.