The Thai Meteorological Department (TMD) warned the temperatures in Thailand may keep rising until the end of this month, before the weather will later improve because of the onset of the rainy season.
The TMD has forecast that from April 28 to May 7, temperatures in Thailand will remain high.
From April 28 to May 2, hot weather will prevail due to low chance of rainfall, except for around the Andaman Sea area in the South, it said.
The wind direction will start to change from May 3 to 7, with the appearance of rain clouds in the Northeast and the East. Temperatures will then moderate.
The department said Thailand's summer normally runs from mid-February until mid-May.
Considering that tropical zones receive perpendicular rays of the sun, Thailand – which is located near the equator – will fully receive the sun’s rays at noon, especially this month, with heat covering the country and pushing temperatures up to more than 40 degrees Celsius.
From May to October, the southwest monsoon will hit the country and cause the increase of rainfall, which can help reduce the overall temperatures.
The temperature may also not be high in September due to rainfall and humidity.
On Sunday, the highest temperatures in the north ranged from 39 to 44°C, while temperatures in the northeast ranged from 42 to 44°C.
Temperatures in the central plain were measured at 39 to 44°C and the east ranged from 35 to 42°C.
In the southern region, temperatures ranged between 35 and 41°C in the east, while the western side ranged from 35 to 38°C.
Temperatures of around 35 to 42°C were detected in Bangkok and its adjacent provinces.
Seree Supratid, director of the Climate Change and Disaster Centre at Rangsit University, on Saturday posted on his Facebook page that overall temperatures in Thailand will rise until the second week of next month, before dropping in June.
Mr Seree noted that global temperatures will continue to rise due to the use of fossil fuels.
The country may also encounter 18 tropical storms from May to October, he added.