How does the time traveller change the weather

From the text:

"I turned frantically to the Time Machine, and strove hard to readjust it. As I did so the shafts of the sun smote through the thunderstorm. The grey downpour was swept aside and vanished like the trailing garments of a ghost."

From the text:

"I turned frantically to the Time Machine, and strove hard to readjust it. As I did so the shafts of the sun smote through the thunderstorm. The grey downpour was swept aside and vanished like the trailing garments of a ghost."