Every morning this summer, I put two 1.5-litre bottles of water in the freezer and headed to the library to work under the air conditioning. By nightfall, the bottles had to be frozen solid again. At night, I placed them next to the two fans in my room, so the ice could absorb at least some of the heat.
This year, for 52 nights in a row, temperatures in Barcelona barely dropped below 30°C. Torrid nights. They are more dangerous than scorching sunny days. They are called silent killers because under these conditions the body cannot properly rest or cool down, and eventually it starts to fail. Catalonia is counting the dead. In the first half of August, 575 deaths may have been linked to the heat, more than half of Spain’s total over the same period. Blood vessels dilate, the blood thickens, blood pressure fluctuates, and the heart fails to keep up.
As I walk through 32°C heat towards the library, there is only one thing on my mind: I hope it is open today. Barcelona’s librarians have been on strike this summer, and sometimes, with no notice, the staff simply do not come in because they are at demonstrations and union meetings.
Libraries are the backbone of Barcelona’s network of refugis climàtics, or climate shelters. The network includes around 500 places across the city: parks, shopping centres, museums, as well as several pharmacies and supermarkets.
For me, the library is the ideal climate shelter. It has quiet corners where I can work on Verba. Some of Barcelona’s libraries have even been named among the best in the world. And believe me, they really are.
This is how, every summer, we become climate refugees in our own city.
And What About Air Conditioning?
Just a few years ago, I used to laugh at reviews from American tourists horrified by the lack of air conditioning not only in some restaurants and public spaces, but even in three-star hotels. Summer nights were difficult for all of us back then, of course. But we were talking about a handful of sweltering nights, not 52 suffocating ones in a row. You could live with the hum of a fan. You could even get used to it. So the American panic read as fussiness, as people spoiled by a certain level of service.
Nobody is laughing at them now.
It is not just Spain. Europe as a whole is notorious for its lack of air conditioning.
One reason is the high cost of electricity. Some people would rather endure the heat and save €50–70 a month. For others, that money is simply too much. And installing air conditioning in some heritage buildings can cost a fortune, or take years of negotiations and approvals with city hall.
There is no air conditioning in the rented flat I share with three friends. And one system would probably not be enough for a hundred-square-metre apartment anyway.
This year, though, we got ourselves a pingüino. That is what portable floor-standing air conditioners are commonly called here. At least now we can cool our large living room for a while, the room that faces the sun during the day.
Watching my neighbours, I have realised that many people simply do not know how to live through extreme heat. Instead of keeping their windows closed, they open them, hoping that a breeze or a draught will bring some relief.
What comes in is the street heat. It takes over every corner of the flat and starts testing just how much the people inside can withstand.
Keep the windows closed and the fans running, as official guidance and public-service campaigns recommend, and the heat becomes considerably easier to bear.
What Should We Expect?
July 2026 was the hottest July on record in Catalonia, according to Meteocat data going back to 1950. Temperatures reached 40°C or more somewhere in Catalonia on around 20 days. The previous record was 16 days, in 2025. On 8 July, the Fabra Observatory registered 40.9°C — the highest reading there since 1914.
Santi Segalà, head of forecasting at Meteocat, has been the most quoted voice of this summer. He says August and September are expected to remain warmer than normal. The thresholds are rising faster than people can adapt.
“It cannot be that every year the warning threshold is pushed higher,” he says. “In the end we will be issuing alerts for 42°C, when at 39°C the risk to health is already enormous.”
Researchers at UPC warn that night-time heat kills more people than daytime heat. In Barcelona, between 2007 and 2018, more deaths were tied to night-time lows than to daytime highs. They call night-time heat a “silent killer”: the body does not recover in sleep.
In summer, Barcelona gets caught in a brutal weather trap. Persistent North African air does not leave. The city becomes a heat island. Buildings and streets store the heat; the sea runs warmer than usual; the air does not cool at night, and the humidity makes the heat feel even heavier.
Days above 40 have stopped being a shock. Nights at 25 have not.
The Catalan coast is the part of Spain where the number of heatwave days is expected to rise the most by 2050, according to researchers at the Barcelona Supercomputing Center and Trescientosmil. Across the country as a whole, they project that the number of extremely hot days will triple.
According to ICTA-UAB and high-resolution climate models, heatwaves in the Barcelona metropolitan area could become 4 to 6 degrees more intense by the end of the century.
The experts are pointing to a new normal that has not peaked yet.
Before bed, I take a shower. I recently read that it should not be ice-cold. The water should be cool. Otherwise, dilated blood vessels can constrict sharply, and you could end up having a heart attack or a stroke. But I still stand under cold water. I try to cool my head properly. I put a palm to my skull and feel how hot the bone has become.
After the shower, the only job is to fall asleep fast. The frozen bottles by the fans do their small work. That is how you get a chance at five or six hours. I wake up because there is nothing left to breathe. By then, even the condensation on the bottles is gone. They are completely dry. I take them back to the freezer. I have been living like this for about two months.
Barcelona at 50°C?
In the middle of this summer, on 15 July, Mayor Jaume Collboni officially launched the “Barcelona at 50°C” project. It is part of the so-called Heat Plan 2025–2035.
City services are already learning how to work and coordinate as if Barcelona were under attack from killer heat. First, working groups are developing the plan. In February 2027, there will be a simulation for command centres and emergency services. Then, in September, an operational field exercise will reproduce different systemic failures that 50°C heat could set off: power, transport, water, hospitals, social services and telecommunications.
The point is to see where the city comes apart at temperatures that are “almost incompatible with life.” Collboni said it plainly: “Today Barcelona reaches 40 degrees, and fifty years ago nobody imagined that. We have an obligation to prepare the city for 50.”
Nothing like this existed in 2019, when I moved here, or before that. Cascading infrastructure failure was not a scenario anyone was running. Now officials and residents are almost obsessed with it.
In April 2018, Barcelona adopted a Climate Plan that runs to 2030. The city was preparing for more frequent heatwaves and trying to protect vulnerable people from extreme weather.
The measures assumed that by 2050 the city would face four or five heatwaves, roughly once every four years, while daytime temperatures above 30°C would last around 50 days a year.
The authorities planned a network of climate shelters within a five-to-ten-minute walk for 100 percent of the population. The city bet on more greenery, on adapting schools and housing, and on revising alert thresholds. Not a word about 40°C as a trigger for systemic collapse. Still less about 50°C.
Catalonia’s plan for preventing the effects of heatwaves used thresholds based on the 98th percentile of summer maximum temperatures, roughly 33–34°C. City measures included distributing water to homeless people, calling vulnerable residents and opening air-conditioned spaces. There was no modelling of infrastructure under 40–50°C conditions. Temperatures like that were treated as an almost unreachable ceiling.
Protocols for 40°C came later. They now look like this: fase emergencia 2 is activated if the forecast exceeds 40°C.
Nobody seriously modelled a day when power, the metro, water and communications fail at once. Fifty degrees was science fiction. Now it is an official plan, with drills in 2027.
The shift in thinking is huge: from “protect people from the heat” to “check whether the city holds together at all.”
Barcelona’s model for dealing with killer heat follows Paris to some extent. Back in 2023, the French capital ran its Paris at 50°C crisis exercise, modelling a heat dome and the failure of urban systems. After that, the issue entered the Climate Action Plan 2024–2030: more cooling shelters, the option of turning schools, gyms, tunnels and even car parks into emergency cooling spaces, support for residents on upper floors, and the idea of night programmes in cool public spaces.
Why Does Barcelona Not Cool Down?
There are several reasons. The most discussed is anthropogenic climate change. According to the WHO, Europe is the fastest-warming region in the world. And the Mediterranean is one of the global hotspots of warming.
Then there is Barcelona’s urban fabric. The masterpieces of modernist and neo-modernist architects are packed into a city that becomes denser every year. Asphalt, concrete and the buildings themselves absorb heat during the day and generously give it back at night. This is the urban heat island effect. In Barcelona, differences of up to 7–8°C have historically been measured between the hottest central areas and the outskirts under certain conditions.
And then there is the Mediterranean itself, which has long since turned into a giant heat battery beside which the city is trying to cool down. In August, the western Mediterranean was around 4°C warmer than normal, while some readings near the Balearic Islands reached 33°C. AEMET is blunt: an overheated sea contributes to very warm nights along the coast and makes the oppressive humidity even worse.
But a nearly conspiratorial explanation also formed in my head. This year’s heat has coincided rather neatly with a record boom in data-centre construction around the world. They are notorious consumers of water and enormous generators of waste heat. People living nearby can physically feel that it has become hotter.
It turns out that this is also being discussed in Barcelona, though mostly in the broader context of the environmental burden of data centres.
In June, RAC1 highlighted a study suggesting that data centres can raise temperatures in nearby areas by 2–9°C, with the effect measurable up to 10 kilometres from a facility. In Catalonia, the number of data centres has grown by 416 percent in four years. There are now 21 operating facilities, with another 26 planned in Cerdanyola, Zona Franca, Sant Adrià and other areas. The Generalitat, meanwhile, sees them as part of its digital strategy.
The local fight is broader than heat. Ecologistes en Acció is calling for a moratorium on mega data centres and is attacking them mainly over electricity use, water consumption, emissions and the relatively small number of jobs they create. In June, Barcelona even hosted a separate public discussion on AI, financialisation and the material impact of data centres.
And the heat issue is not abstract for Barcelona. There are studies based specifically on a Barcelona data-centre model that examine the enormous amount of waste heat these facilities produce and the possibility of using it for district heating instead of simply releasing it into the environment. A new Mediterra project near Barcelona is also being designed to feed residual heat into municipal systems. In other words, the industry itself acknowledges the physical reality of the problem: servers generate a huge amount of heat. The only question is where to put it.
So Barcelona does not cool down for several reasons. Climate sets the background. The stone of the city breathes heat back out at night. The sea offers no relief. And new digital infrastructure may add another two degrees around it, while also forcing people to argue about further construction and make compromises.