French heatwave ties for country's longest on record

France's latest heatwave has already tied for the country's longest on record after lasting more than three weeks, the country's meteorological service said Thursday.

France has been hit by three heatwaves in quick succession in a historically hot European summer during which the continent has seen widespread drought and wildfires fuelled by global warming.

The latest, which began in late July and has yet to be officially declared over, "continued Wednesday, for a duration of 23 days," Meteo-France told AFP.

"It is the longest heatwave on record, tied with July 1983."

The national average temperature was 24.7C for Wednesday, including both daytime and nighttime readings, the service said.

Meteo-France defines a national heatwave as a period lasting several days during which temperatures are significantly higher than normal.

A heatwave begins when the indicator reaches or exceeds 25.3C for one day and the national average temperature remains at or above 23.4C for at least three consecutive days.

It ends when it drops below 23.4C for at least three days in a row or falls briefly below 22.4C.

A spell of unusually warm weather in May, for example, was not intense enough to meet the agency's threshold for a heatwave.

In addition to the current heatwave, France also suffered under a 14-day spell in June and 16 days in July.

The June heatwave was record-breaking in terms of intensity, with temperatures spiking above 40C in many places.

However, a heatwave in August 2003 remains the most severe observed to date -- based on an indicator combining heat duration and intensity.