Victor Frankenstein has always been interested in the inner workings of the universe. Once he saw a bolt of lightning that struck a tree. This experience led to his explorations of lighting and electricity. When he was lightning, he became fascinated with the theories of galvanism. It is apparent that lightning and thunderstorm are the natural phenomena that influenced Frankenstein.
Detailed answer:
Victor has been interested in chemistry and anatomy since he was a boy. He pondered about the questions of life and death a lot. During the studies, his ambition was to become a scientist and explore the ways to create a new living being. To do that, he conducted research and experiments. During a thunderstorm, he saw lightning. He focused on using electricity in his work. Victor became fascinated with the theories of galvanism. It helped him figure out the solution to revive his creature.
The lightning is never mentioned as one of the steps of creating the monster. The book does not describe the process Frankenstein used. But seeing a lightning bolt when he was a boy had an impact on Victor. As a result, he was inspired to experiment with science. At the same time, he saw the oak tree being destroyed by lightning in chapter 2. He realized that nature has a destructive power. Victor’s real motivation was never to create. His successful creation of the monster showed that he was capable of destruction.