The 35-year-old man died after after he, an 11-year-old child and a 43-year-old woman were struck by lightning when sitting at a table under a tree on Saturday afternoon, police said.

Paramedics tended to the injured before they were taken to hospital. A rescue helicopter flew the boy to a hospital. He was now somewhat better, a spokesman said on Sunday afternoon.

The 43-year-old woman was injured in the incident in the community of Unterensingen, and remains in critical condition, police say.

Her children – a four-year-old boy and a girl just under 11 months old – suffered shock. They were in a bicycle trailer when the lightning struck.

Police said about 15 people had sought shelter in a barn when the thunderstorm hit.

-with AAP