Two lightning strikes left a man dead and a woman injured Monday as the sudden departure of the rainy season and a high-pressure system from the Pacific sent temperatures soaring in much of the nation.
In Tokyo, three men in their 50s and 60s were struck by lightning near the Arakawa River in Kita Ward after a thunderstorm developed, leaving one dead, police said.
According to witnesses, the three were hit while sheltering under a tree at around 3:50 p.m. Police are still trying to identity the dead man.
A woman in nearby Saitama Prefecture was later knocked unconscious in a separate lightning strike in Tokorozawa at around 5:15 p.m.
The woman, 53, was struck while working on a farm and remains unconscious, police said.
The Meteorological Agency said temperatures soared well into the 30s in much of the nation after active convection currents near the Philippines stimulated a high-pressure system in the Pacific earlier than usual.
It also said the rainy season had come to a premature ending virtually nationwide, two days after declaring it over in the Kanto-Koshin region, which includes Tokyo.
Areas in the north, the northeast and the Sea of Japan side of central Honshu are still getting rain. In regions southwest of central Japan, the rainy season ended six to 13 days early.
Predicting highs of over 35 in many places, the weather agency issued a high-temperature advisory warning people to stay hydrated and to use air conditioning to prevent heatstroke.
By Monday morning, the mercury had hit 36.2 in Kamikitayama, Nara Prefecture, 36 in Tajimi, Gifu Prefecture, 35.8 in Hamamatsu, Shizuoka Prefecture, and 35.7 in three cities in Yamanashi, Kyoto and Tottori.
On Sunday, the heat wave caused the death of a 50-year-old man and sent at least 740 other people to the hospital due to overheating.
The man who died was in the city of Shikokuchuo, Ehime Prefecture, when he was taken to a hospital. He apparently died of heatstroke.
Heatstroke can usually be confirmed by a core body temperature above 40.5 degrees, but fainting may also be a symptom. Other clues include headache, dizziness, failure to sweat, cramps or nausea, rapid pulse or breathing, or even seizures.
According to local police and fire stations, 10 junior high school students taking part in a baseball game in Saitama Prefecture were taken to a hospital on Sunday after exhibiting symptoms of heatstroke.
Marathoners were also affected, with six runners in Aomori Prefecture and others in Tottori hospitalized.
Off the coast of Matsuyama, Ehime Prefecture, a 15-year-old boy drowned, while in the city of Gero in Gifu Prefecture, a 10-year-old girl and her 4-year-old brother were swept away by the Hida River.
Both siblings were washed away when the girl tried to rescue her brother after he slipped into the river.