Bangladesh last month saw the hottest average April temperatures since the country began keeping weather records in 1948, a senior forecaster told AFP on Wednesday.

"2024 was the hottest April since 1948 in terms of hot days and area coverage in the country," Bangladesh Meteorological Department senior forecaster Muhammad Abul Kalam Mallik said.

Bangladesh remains in the grips of a suffocating heatwave that prompted authorities to close schools nationwide, with temperatures not expected to moderate until Thursday.

"This year the heatwave covered around 80 percent of the country. We've not seen such unbroken and expansive heatwaves before," Mallik said.

Mallik said the 30-year average daily temperature for April between 1981 and 2010 was 33.2 degrees Celsius, but this year weather stations around the country recorded temperatures of between two and eight degrees higher.

He added that Bangladesh had not seen the usual pre-monsoon April thunderstorms which normally cools the South Asian nation ahead of summer.

"Bangladesh gets an average 130.2 millimetres of rain in April. But this April we got an average of one millimetre of rain," he said.

Mallik said the bureau was checking data to confirm whether this year marked record low rainfalls for April.