Photo/Illutration People cool off under mist sprinklers in Fukuoka’s Hakata Ward on Aug. 1. (Kengo Hiyoshi)

Japanese who are complaining of suffering through the hottest summer they've ever endured now have their belief endorsed by the country’s weather agency.

The average temperature from June to August this year will be the highest since record-keeping began in 1898, according to an expert panel of the Japan Meteorological Agency on Aug. 28. The previous record was set in 2010.

This year Japan also saw its hottest July and second hottest June on record, and highest temperature records were broken at 106 of 915 observation points across the country between July 16 and Aug. 23.

“Several factors came together to cause the extreme summer heat,” said Hisashi Nakamura, the JMA's panel chief and a professor at the University of Tokyo’s Research Center for Advanced Science and Technology.

High-pressure systems from the Pacific Ocean covered the main island of Honshu starting in late July, causing temperatures to soar. And in August, typhoons brought in warm air masses as they slowly moved northward.

Other factors that contributed to the heatwave include westerlies flowing in higher latitudes than usual and record-high sea surface temperatures.

“This summer’s heat stands out on record and it’s been a very unusual summer,” said Nakamura.

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Hisashi Nakamura, left, who heads the Japan Meteorological Agency’s expert panel, speaks at the agency in Tokyo on Aug. 28. (Takuya Miyano)