A massive mild to moderate heatwave engulfed three-fourths of Bangladesh on Tuesday, affecting 49 districts, with chances of it continuing, more or less, over the next week, said the Bangladesh Meteorological Department.

A mild heatwave occurs when the day temperature ranges between 36C and 37.9C while a moderate heatwave refers to the temperature remaining between 38C and 39.9C.

On Tuesday, Bangladesh’s highest maximum day temperature of 38C was recorded in Nilphamari, a northern district. Dhaka recorded its maximum day temperature to be 36.8C.

‘Brief rain spells might slightly lower the temperature but overall hot conditions will prevail,’ said meteorologist Md Shaheenul Islam.

Depending on the rain spells, the number of heatwave-affected areas might  fall or rise over the next week until a heavy wet spell set in, which is likely around June 17, he said.

On Tuesday, a moderate heatwave swept the district of Nilphamari while a mild heatwave swept the rest part of Rangpur division and the divisions of Rajshahi, Dhaka, Mymensingh, Khulna and Sylhet, and the districts of Brahmanbari and Feni.

Bangladesh’s highest rainfall of 24mm in the 24 hours until 6:00pm on Tuesday was recorded in Hatiya.

Except for light to moderate rainfall in Khulna and Chattogram, there was no rain recorded in the country in the 24 hours.

The heatwave began on June 7, the day of Eid-Al-Azha. The heatwave followed a massive wet spell triggered by the depression that formed in the Bay of Bengal in late May. The depression caused heavy to extremely heavy rainfalls over vast swathes of land stretching from the plains along Bangladesh coasts to the Himalayan highlands in Nepal, India and Bhutan.

The wet spell preceding the heatwave even triggered flash flooding and landslides and cost lives across border.

June is the first monsoon month but nevertheless get heatwaves. Heatwaves, in fact, are becoming even more frequent during June.

This year monsoon made the earliest onset-ever since 1981.