Power cuts have been most widespread in the late evenings and early mornings, data from the Power Grid Co of Bangladesh showed
Local police OC Taimur Bakht Chowdhury said that this happened on Wednesday at Birat Union of the Upazila.
The boat was heading to Ajmiriganj town, when the lightning struck leaving the four dead on the spot.
Those killed have been identified as Musa Mia, 50, Khitish Sutradhar, 20, Ranjit Sutradhar, 45 and Prosen Sutradhar, 22.
The injured have been taken to the Ajmiriganj Upazila Health Complex.