The annual extravaganza, usually held in Nagoya, sees thousands of people from all over the world embody their chosen anime, manga and gaming stars in elaborate costumes, outlandish hairdos and zany face paints.

Organisers said after this year's 23rd shindig ended Sunday -- 247,200 people attended over three days -- that next year's will also be in August, but for 2027, it will be in November.

"This change was made in response to the extreme heat and other weather conditions," the event's executive committee said in a statement on Tuesday.

The move was also to "strengthen our efforts to accommodate more international participants and to take into account trends in domestic and international tourists," it said.

Japan this week set a new high of 41.8C, with tourist hotspot Kyoto in late July seeing 40C for the first time since records began.

Summer last year was the joint hottest on record, equalling 2023, and was followed by the warmest autumn since records began 126 years earlier.

Last month, 38,608 people were treated in hospital for heatstroke, data showed Tuesday, down from 43,195 in July 2024.

Preliminary findings from the Tokyo Metropolitan Medical Examiner's Office found 56 people in central Tokyo likely died from heatstroke this June and July.

Of those, 54 died indoors, and most were aged 60 or older. Thirty-eight of them had air-conditioners but did not use them.