Never has been so hot so early in Europe: Spain +42,9°C (Morón de la Frontera), Portugal +40,5°C, (Mertola), Italy +40,2°C (Lentini), North Macedonia +37,3°C (Skopje), Ukraine +37,2°C (Izium), Serbia +36,1°C (Cuprija), Romania +35,2°C (Drobeta), Hungary +34,6°C (Debrecen)
Marek Kučera 
As the summer of 2025 begins, Europe is already witnessing a powerful early-season heatwave that has shattered temperature norms across multiple countries. From the Iberian Peninsula to Eastern Europe, thermometers have surged well above seasonal averages, with June records being challenged or even surpassed in several locations.
Unprecedented Early Heat
The first week of June has already brought extreme heat to many parts of southern and eastern Europe. What is particularly alarming is not only the intensity but also the early timing of these heatwaves. Normally, such extremes are associated with late July or early August, not the first ten days of June.
Here are some of the most remarkable maximum temperatures recorded so far:
- Spain: +42.9 °C in Morón de la Frontera – This scorching reading is among the highest ever recorded in Europe in early June and is only marginally lower than Spain’s national June record (43.9 °C in Girona, 2022). The region of Andalusia is no stranger to heat, but such early-season values raise red flags about long-term warming trends.
- Portugal: +40.5 °C in Mértola – Located in the interior of the Alentejo region, Mértola is known for hot summers, but crossing 40 °C in early June is extremely rare. This temperature could rival national early-June records, underscoring the severity of this heat episode.
- Italy: +40.2 °C in Lentini, Sicily – Southern Italy and Sicily are historically hot, yet reaching over 40 °C this early in the season is an alarming indicator of what may come later in July and August.
- North Macedonia: +37,3°C in Skopje – a record for early June.
- Ukraine: +37.2 °C in Izium – This represents a remarkable spike in heat in Eastern Europe. For a country that typically sees its hottest weather in late summer, such a temperature so early suggests the region is entering a prolonged hot spell.
- Serbia: +36.1 °C in Ćuprija – This central Serbian town has exceeded what would be expected even in mid-July. Such extremes are rare and potentially harmful, especially when they occur without gradual acclimatization for vulnerable populations.
- Romania: +35.2 °C in Drobeta-Turnu Severin – A city on the Danube, Drobeta has experienced one of the hottest starts to June on record. Combined with high humidity, the heat index pushed well into the danger zone.
- Hungary: +34.6 °C in Debrecen – Eastern Hungary was hit with sharp and early heat, bringing uncomfortable nights and daytime maximums nearing all-time early summer records. A record for early June.
Synoptic Conditions Behind the Heat
The cause of this exceptional warmth lies in a persistent high-pressure system parked over southern and central Europe. This “heat dome” has blocked cooler Atlantic air from entering the continent, allowing Saharan air masses to surge northward. With cloudless skies, sinking air, and strong solar radiation, surface temperatures have soared.
Additionally, dry soils from a relatively dry spring in Iberia and parts of Eastern Europe have reduced evaporative cooling, amplifying the heat further.
Early Warning for the Summer Ahead?
While one heatwave does not make a trend, this early June event is consistent with broader climate signals: longer, more intense, and more frequent heatwaves across Europe. The IPCC has warned that southern and eastern Europe are hotspots for extreme temperature events due to climate change, and this June appears to be a vivid example.
If these temperatures are already occurring in early June, there is a strong possibility that record-breaking highs in July and August could follow—especially if similar synoptic patterns persist.
Health and Infrastructure Impact
High temperatures this early in the year pose significant risks:
- Health: Populations are less acclimatized to heat in June. Sudden spikes in temperature increase risks of heat exhaustion and heatstroke, especially among the elderly and outdoor workers.
- Agriculture: Crops such as wheat and maize, especially in Eastern Europe, are entering key growth stages. Heat stress combined with water shortages may reduce yields.
- Energy Demand: Spikes in air conditioning use have already begun, stressing electrical grids and raising peak energy consumption levels.
Conclusion
The June 2025 heatwave across Europe is more than just a statistical anomaly. It is a strong signal that the continent’s climate is rapidly changing. With Spain breaching 42.9 °C, Italy and Portugal above 40 °C, and Eastern Europe seeing mid- to high-30s, this month could be among the hottest Junes ever recorded.
Our latest forecast of national maximum temperatures during the upcoming heatwaves in June 2025 you will find here: https://mkweather.com/heatwaves-in-europe-should-be-even-more-deadly-spain-and-turkey-46c-france-and-italy-42c-balkans-continental-europe-40c-the-uk-scandinavia-35c/.
Illustration picture: https://www.vecteezy.com/photo/54508289-stunning-golden-wheat-field-at-sunset
Marek Sadowski 