The people were killed on Sunday evening as the state of Andhra Pradesh was lashed by thunderstorms and heavy rain.
Among others who had a narrow escape were two women's cricket teams who were playing when a tree nearby was hit by lightning.
A district cricket official in the town of Guntur, where the women were playing, said: "It was a miraculous escape for the players and the people at the grounds."
The deafening sound caused by the strike left players and spectators fleeing the ground in panic, the official said.
The friendly match between the women's teams Andhra and Tripura was abandoned, The Hindu newspaper said.
Among those who died were Satish Kumar from Madhya Pradesh, who was killed while he was drilling a borewell in a farm, The Hindu said.
Also, a 60-year-old woman called L Venkatasubbamma and her daughter-in-law Venkataramana,30, died while working in their farm.
Weather officials said a low-pressure system over the Bay of Bengal was to blame.
Lightning strikes are common during India's monsoon, which runs from June to September, but officials said that the number of deaths on Sunday was unusual.