Yahoo! Japan via nippon news/YouTube
Temperatures in Japan unexpectedly rose after the end of a rainy season this summer, with highs of about 37 degrees Celsius (98.6 degrees Fahrenheit) expected this week.
At least 11 people have died, and 5,600 others have been taken to hospital due to the heat.
A 28-year-old part-time theme park worker died from heatstroke after practising a dance in the heat on Sunday.
At least 11 people, including a theme park mascot, have died due to an unexpected heat wave sweeping Japan.
An additional 5,664 people around the country were taken to hospital with heat-related medical issues last week, the Japanese government said Tuesday, according to the Kyodo news agency.
Temperatures unexpectedly rose after the end of the country's rainy season, with most of the country's monitoring posts recording highs of over 30 degrees Celsius (86 degrees Fahrenheit), according to the Japan Meteorological Agency (JMA).
The city of Nagoya, central Japan, is due a high of 37 C (98.6 F) on Thursday and Friday, according to the JMA.
Yohei Yamaguchi, a 28-year-old part-time amusement park worker, died from heatstroke after practising a dance outdoors in a 16-kilogram (35.3-pound) mascot costume on Sunday night, Kyodo reported.
Yamaguchi had been practising the dance on an outdoors stage in Hirakata amusement park for about 20 minutes from 7:30 p.m., and lost consciousness around 8 p.m., Kyodo and The Asahi Shimbun reported, citing local police.
He died shortly after being rushed to hospital, Asahi reported. Temperatures were about 28.7 C (83.7 F) at the time, the newspaper said, citing the meteorological agency.
The operator of Hirakata Park, the amusement park where Yamaguchi worked, apologized for the death and said it would "find the cause of it and work to prevent it from happening again," according to Asahi.
Hirakata Park has also canceled all mascot-related events this summer, Kyodo and Asahi said.
The Asahi Shimbun via Getty
Last summer, seventy-seven people died in an unprecedented heat wave in Japan, with temperatures reaching 41.1 C (105.8 F). The JMA classified it as a natural disaster.
India has also seen highs of more than 50 C (122 F) this year, leaving more than 100 people dead.