TOKYO, July 6 — Japan is sweltering under an intense heatwave, with temperatures hitting the high 30s across much of the country today, prompting authorities to issue heatstroke alerts in 19 prefectures — including the first warnings this year for central Tokyo and neighbouring Kanagawa.

According to the Japan Meteorological Agency, the current heatwave is expected to persist until mid-July, marking a rare occurrence “seen only once in a decade.”

The agency attributes the extreme weather to climate change and a stronger-than-usual Pacific high-pressure system that has brought an unusually early end to the rainy season in western Japan.

The Japan Times reported today that temperatures climbed to 38.3C in Kuwana, Mie Prefecture, 37.9C in Toyota, Aichi Prefecture, and 37.7C in several cities including Tajimi in Gifu, Hamamatsu in Shizuoka, and Kofu in Yamanashi.

The Japan Sport Association advises cancelling outdoor sporting events if the heat index — which factors in temperature, humidity and solar radiation — exceeds 31.

In Tokyo, the index reached 32.2C by 11am, prompting the Japan Association of Athletics Federations to reschedule events during its three-day national championships at the Japan National Stadium in Shinjuku. Today’s adjustments followed similar delays on Friday and Saturday.

The early heat has been exacerbated by the premature conclusion of the rainy season in regions such as Chugoku, Shikoku, Kinki, and northern Kyushu, where the season ended nearly 20 days ahead of schedule — the earliest on record.

June was Japan’s hottest ever, with average temperatures 2.34C above the historical norm, the Meteorological Agency said. The trend is in line with rising global temperatures, as the agency warned that climate patterns are shifting due to global warming and changing wind systems.

Authorities are urging residents to take precautions against heatstroke, including staying hydrated, avoiding outdoor activity during peak hours, and seeking cooler indoor environments.