‘This isn’t just another hot week’: Europe to swelter in 40°C with experts warning of hidden dangers

Sizzling temperatures are creeping back into Europe, just weeks after a deadly heatwave gripped the continent.

Spain’s meteorological agency AEMET has already placed clusters of the country under a yellow weather warning due to a “notable rise” in temperatures - while an orange warning for rainfall and storms has been issued in the northeast.

Forecasters predict that Seville, Zaragoza, and Córdoba will be hit the hardest, with temperatures pushing towards 40°C into next week. Tropical nights, where the temperature doesn’t fall below 20°C during a 24-hour period, are also expected – providing locals with little relief.

France – which witnessed multiple deaths during last month’s unprecedented heatwave – is bracing for projected highs of 39°C in the southwest and Bordeaux region.

In Portugal, temperatures are set to rise from Saturday (20 June) onwards and are likely to remain very high next week, with temperatures potentially reaching 40°C or higher in some regions, according to meteorologist Maria João Frada.

“We are already talking about temperatures of around 35 to 40°C by the start of next week, [but] the 40°C mark will be more confined to inland regions, the inland part of the Douro Valley, the Tagus Valley and the interior of the Alentejo,” Frada explains, adding that along the western coast temperatures could reach 35°C.

‘This isn’t just another hot week’

Meteorologists in Italy warn that hot air from the subtropical latitudes on inland North Africa will draw over the country next week, bringing with it blistering temperatures in the south – while Florence could see highs of 40°C.

Even typically cooler nations are showing signs of warming up in the coming days.

According to early predictions from weather forecasters at wfy24.com, the interior Danube plains of Bulgaria and Romania are pushing toward 38°C, with Budapest climbing into the 36–37°C range as the ridge extends over the Carpathian Basin.

“This isn't just another hot week; it has the structural fingerprints of an atmospheric blocking event, not a passing warm spell,” Ionna Vergini, founder of wyf24, tells Euronews Earth.

Europe’s ‘structural gap’ against intense heat

Vergini describes the spike in temperatures as a “textbook demonstration of the ‘new normal’, as heat-trapping gases continue to heat the planet.

“What it reveals about preparedness is a widening structural gap,” she says. “Southern Europe has developed a behavioural tolerance to extreme heat: shifted routines, siestas, shutters, etc, but that's a behavioural adaptation, not a biological one, and it doesn't protect the physical infrastructure.”

Electrical grids, even in hotter regions, struggle to cope with surges in air conditioning use – while many public transport systems are built on thermal thresholds designed for the late 20th century, meaning they’re also vulnerable to intense heat.

Last week, the northwestern Italian city of Turin experienced huge blackouts as the May heatwave sparked strain on the local electricity network.

France’s commuter rail and tram-train network Transilien has already urged the public to check train schedules before heading to the station due to potential disruption caused by the heatwave.

The hidden dangers of tropical nights

The incoming rise in temperatures is also met with an increase in tropical nights across much of the Mediterranean.

This phenomenon is already impacting public services such as schools – which are considering changing exam times to help protect students who aren’t sleeping well due to high night-time temperatures.

"Sustained nighttime heat is arguably a greater public health threat than the daytime peak,” explains Vergini. “When lows fail to drop below 20°C and in the worst cases stay above 25°C, what some call 'super-tropical nights' the body is denied its vital recovery window, and the cardiovascular system stays under constant strain to cool the core.

“Excess mortality during heatwaves correlates much more heavily with consecutive high nighttime minimums than with a single hot afternoon.”

Tropical nights are often much worse in cities, due to the urban heat island effect. This is when heat is trapped between tall buildings and absorbed by the large amounts of asphalt and concrete found in cities and then released back into the air.