Temperatures the world over have soared in recent years as climate change creates ever more erratic weather patterns, and Japan is no exception.

Wednesday's new record in the western region of Hyogo surpassed the previous high of 41.1C seen in Hamamatsu in 2020 and Kumagaya in 2018, the weather office said.

The record comes on a day Japan was also on high alert for tsunamis after a massive magnitude 8.8 earthquake in Far East Russia.

In tourist hotspot Kyoto the mercury hit 40C, the first time any of its observation points -- the oldest opened in 1880, the newest in 2002 -- had seen such a high, authorities said.

Japan's summer last year was the joint hottest on record, equalling the level seen in 2023, followed by the warmest autumn since records began 126 years ago.

The Japanese government has issued heatstroke warnings to a large swathe of the archipelago in recent days as temperatures topped 35C at hundreds of observation points.

On Tuesday, the temperature hit 35C or higher at 322 of 914 observation points nationwide, reportedly the highest number since comparative data became available in 2010.

New highs were set in 38 locations, including Gujo in Gifu Prefecture in central Japan, which reached 39.8C, the Japan Meteorological Agency (JMA) said.

The heatwave is forecast to continue, the JMA said, warning of a "significant" rise in temperature in northern and eastern regions.

"Please take care of your health including (avoiding) heatstroke," it said.

- Heatstroke -

A total of 10,804 people in Japan were sent to hospital due to heatstroke last week, the highest weekly figure this year.

In total 16 people died, the Fire and Disaster Management Agency said.

The number is the highest this year, surpassing the previous record of 10,053 people hospitalised in the week from June 30 to July 6.

Every summer, Japanese officials urge the public to seek shelter in air-conditioned rooms to avoid heatstroke.

The elderly in Japan -- which has the world's second-oldest population after Monaco -- are particularly at risk.

Western Europe saw its hottest June on record last month, as extreme temperatures blasted the region in punishing back-to-back heatwaves, according to the EU climate monitor Copernicus.

Dangerous temperatures stretched into July, with separate research estimating that climate change made the heat up to 4C hotter, pushing the thermometer into deadly territory for thousands of vulnerable people and greatly worsening the projected death toll.

Millions were exposed to high heat stress as daily average temperatures in western Europe climbed to levels rarely seen before -- and never so early in the summer.

Several countries recorded surface temperatures above 40C, with heat of up to 46C in Spain and Portugal, the Copernicus Climate Change Service (C3S) said.