As human-caused climate change brings increasingly intense heat waves to Japan, days with temperatures reaching 40 degrees Celsius or higher have now earned a new name ¡ª kokushobi ¡ª courtesy of the Japan Meteorological Agency (JMA), which announced it on Friday.

The term, which uses the Japanese kanji koku (¿á) ¡ª meaning harsh or cruel ¡ª to describe the intensity of the heat, will enter the lexicon used by the JMA in weather forecasts starting this summer.

The new description translates as ¡°severely hot day.¡±

Currently, the agency categorizes days with peak temperatures reaching 25 C or higher as natsubi (summer day), and uses manatsubi (midsummer day) and ³¾¨­²õ³ó´Ç²ú¾± (extremely hot day) for 30 C and 35 C days, respectively.

However, as summer temperatures continued to rise with days topping 40 C being observed consistently over the past several years, the agency decided that there was a need to add a new category to its classification of heat.

The name was decided based on an online survey conducted between late February and late March that received around 478,000 responses. Kokushobi received nearly 203,000 votes, the largest number and more than triple the votes for ch¨­³¾¨­²õ³ó´Ç²ú¾±, meaning ¡°super extremely hot day,¡± which came in second place.

In addition to the survey results, the decision was made based on expert opinion that the name is socially familiar and appropriate in the Japanese language.

This is the first time that the JMA has introduced a new name into its lexicon since 2007, when ³¾¨­²õ³ó´Ç²ú¾± made its debut.

Reports of extreme-temperature days have been increasing in Japan in recent years.

Temperatures topped 40 C on nine days between June and August last year, with the mercury hitting 41.8 C in the city of Isesaki, Gunma Prefecture, on Aug. 5 ¡ª the highest on record nationwide. The year prior saw a total of four days of 40 C heat, with the highest reading of 41 C recorded in the city of Sano, Tochigi Prefecture.

The JMA in February issued a forecast for?a hotter-than-average summer this year, with high temperatures expected across the country.