The thermometer is spiking once again. This Wednesday, July 29, temperatures are flirting with 40°C in the South-West, Paris is approaching 38°C, and a large part of the country is suffocating under a blazing sun. At first glance, this third heat episode of the summer looks like a carbon copy of the previous ones. Yet behind these crushing temperatures, the meteorological mechanics are entirely different. And that difference will be felt in the coming days.
A More Mobile, Less Enduring Heat
The first two heat waves of the summer shared a common trait: they settled in for the long haul. In late June and early July, a vast heat dome trapped hot air over France and Western Europe, preventing temperatures from dropping for several days. This time, the situation is different. France finds itself on the edge of a heat dome that is positioned more over Central Europe.
In concrete terms, a surge of very hot air from the south will cause a temperature peak this Wednesday, but this heat push will not remain stubbornly stalled over the country. As early as Thursday, cooler air from the Atlantic will reach the west and northwest of France, and the heat will subsequently shift eastward.
Less Widespread, but Intense in Certain Areas
Another difference from the previous episodes: this heat wave is set to be less intense on a national scale. The national thermal indicator is expected to reach 27.4°C this Wednesday, a high level but one that is lower than the two previous heat peaks. In late June, this indicator crossed the 30°C mark, and in July, it hit 28.1°C at the height of the heatwave.
However, behind this national average, the reality will vary greatly by region. While the west of the country will quickly find more breathable temperatures as of Thursday, the eastern and south-eastern regions will remain exposed to high heat for longer, with spikes of 40°C expected by the end of the week.
It should be noted that after a lull on Saturday, temperatures could rise again starting Sunday, this time across a large part of the country, except for the Channel coast and part of Brittany. This succession of heat waves remains exceptional: France is experiencing its third heat wave of the summer, a situation only observed in 2017 and 2022.
