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Catalonia breaks night-time heat records in the middle of May
Catalonia has entered a spell of heat unseasonable for May, and this time the impact is felt beyond midday. Minimum temperatures have broken records in several parts of the region, leaving nights more typical of July than late spring. In Barcelona, many residents have again slept with windows open, fans on and the feeling that summer has arrived too early.
The most striking figure was recorded in Portbou, where the provisional low was 28 °C, a record for overnight heat in May. It was not simply a tropical night, but a low very close to the threshold for a torrid night, which begins when the thermometer does not fall below 25 °C.
Barcelona is also already seeing clearly summery values. This Thursday, the forecast gives a high of around 32 °C and a low of 23 °C, with a warm night that barely allows comfort to be regained after the day. Friday will remain hot, although with a slight drop in the high, to around 31 °C.
The Observatori Fabra had already given an initial warning sign in April. On the 10th of that month it recorded an official low of 19.0 °C, the warmest April night in more than a century of data and above the previous record of 18.6 °C, recorded in 1945.
Meteorologists insist that it is not always appropriate to call every intense episode a “heatwave”. Technically, a heatwave requires several consecutive days with extreme temperatures according to specific thresholds. Even so, the current episode does fit an increasingly visible trend: warm nights that arrive earlier, last longer and affect rest more.
In Barcelona, the centre and the most densely built-up neighbourhoods tend to notice this phenomenon before higher or better-ventilated areas. Tarmac stores heat during the day, buildings release it slowly at night and the city takes longer to cool down. That is why the official low can appear moderate on a map but feel much more oppressive inside a poorly ventilated flat.
Extreme heat is also making itself felt in Europe. Record values for May have been reached in the United Kingdom, and in Spain AEMET has placed some temperatures between 5 and 10 degrees above what is usual for this time of year.
The underlying question is no longer whether a particular night breaks a record, but what happens when these episodes cease to be exceptional. For Barcelona, tropical lows are not just a meteorological figure: they change the way people sleep, work the next day and plan the city. More shade, climate refuges, better-insulated homes and green spaces cease to be debates for the future when the heat begins to set in during May.