Five persons were killed in Sirajganj and Rajshahi each, and four in Pabna, Kishoreganj and Brahmanbarhia each, local officials and police said.
Dhaka, Gazipur, Bogra and Natore had two casualties each, while one death each was reported from Habiganj, Naogaon and Niphamari.
The now-defunct SAARC Meteorological Research Centre's former director Sujit Kumar Deb Sharma told BD News that it was natural for thunderstorms to occur in this season.
Two children were killed in Dhaka's Jatrabari area where they were playing football in a field. Doctors were treating three other boys who were rushed to Dhaka Medical College Hospital with wounds caused by the lightning, police said.