The lightning struck the members of a 'Mahadalit' family in Tiwari-basa tola in Udakishunganj block killing Chhitri Devi (40), Samtolia Kumari (16) Shakil Kumar (14) on the spot.
Two others - Deepak Kumar (10) Neharuia (1) - suffered burn injuries, District Magistrate Upendra Kumar said.
The injured were admitted to a Primary Health Centre (PHC) for treatment, he said.
In Murliganj block, one Satyen Yadav (25) was fatally struck by lightning while he was ploughing a field at Nadhi village Kumar said.
A cattlehead also perished in the mishap.
The local authorities gave Rs 1500 each to the kin of the victims under the Kabir Cremation Scheme, District Magistrate said.
