The weather agency warned that "the rainy season ended earlier than usual this year" and that more heat strokes were feared in people who may not acclimatized quickly enough to the return of sweltering heat.

Japanese media said this year's rainy season was the shortest on record. It usually ends in mid- to late July. Public broadcaster NHK cited weather officials as saying that temperatures will rise to new highs in the next two weeks.

Temperatures soared to 35 degrees Celsius (95 degrees Fahrenheit) in the past three days. Weather officials say that a short period of rains coupled with extreme heat threatens the nation's water supply.