Japan sweltered under an unseasonal heatwave yesterday that rewrote records for the month of May, as the mercury surged above 38 deg C in many parts of the northernmost island of Hokkaido.
The temperature hit 39.5 deg C in the coastal town of Saroma at 2.07pm (1.07pm Singapore time) in north-east Hokkaido, surpassing the previous national record for May - 37.2 deg C - set in 1993 in Chichibu city in Saitama prefecture, north-west of Tokyo.
Temperatures have never topped 38 deg C in Hokkaido, the Japan Meteorological Agency said. The previous high for Hokkaido was 37.8 deg C, recorded in the town of Otofuke on June 3, 2014.
This was also the first time that temperatures have surpassed 35 deg C in Hokkaido in May.
The Hokkaido Railway Company, or JR Hokkaido, cancelled at least 40 train services in eastern Hokkaido over derailment concerns amid fears that the extreme heat may have distorted the railway tracks.
The weather agency said the current heatwave is due to a warm air mass enveloping the entire Japanese archipelago, which is not typically seen until the peak of summer. The unseasonal temperatures are expected to continue through today before subsiding.
Kyodo News said that out of 926 weather-monitoring posts across Japan, temperatures breached 35 deg C at 53 locations and 30 deg C at 513 spots.
The extreme heat set social media abuzz.
Many Japanese were surprised that Hokkaido, known for its cold winters, would be even hotter than tropical south-western Okinawa. Some were also concerned they would be in for a hellish summer that would be even more brutal than the one last year.
A heatwave last year, which the government designated as a natural disaster, pushed the temperature to an all-time national high of 41.1 deg C in Kumagaya, east of Tokyo, on July 23. At least 133 people died nationwide, while more than 55,000 were treated for heat exhaustion between July and August.
Yesterday's heatwave left two people dead, while at least 575 others were taken to the hospital due to heatstroke symptoms, according to a Kyodo News tally.
Comparatively, central Tokyo experienced daytime highs of 32.6 deg C, while Okinawa's capital Naha enjoyed a balmy high of 28.3 deg C. Hokkaido's capital Sapporo felt highs of 32 deg C.
The weather agency has issued advisories urging preventive measures against heatstroke, such as drinking water frequently and wearing hats or caps, or using a parasol.