Greece is bracing for the fifth and most intense heatwave of summer 2026, with temperatures soaring above 40°C in multiple regions starting today, August 22. The extreme heat is expected to persist through Wednesday, peaking on Sunday, August 23 — dubbed a “boiling cauldron” day by meteorologists.
Sunday: The Hottest Day of the Week
Sunday will bring scorching conditions nationwide. Maximum temperatures are forecast to reach 39°C in Athens and Attica, 40°C in Serres, Karditsa, Lamia, Argos, and parts of southern Crete, and 39°C in Arta and Agrinio. Overnight lows won’t offer much relief — staying around 30°C in urban centers like Athens. Humidity levels remain relatively low, but the combination of intense solar radiation and stagnant air will amplify heat stress.
Regional Forecasts
In Athens and Attica, expect clear skies with only scattered clouds during the afternoon and early evening. Temperatures will range between 26°C and 39°C, with light northerly winds up to 4 Beaufort — reaching 5 Beaufort along eastern coastal areas.
Thessaloniki will see mostly sunny conditions, with occasional thin cloud cover in the afternoon and early evening. Isolated thunderstorms and brief squalls are possible over nearby mountainous areas during peak heating hours. Temperatures there will hover between 25°C and 38°C, with light, variable winds (2–3 Beaufort) shifting to southerly in the afternoon.
Across the Ionian islands and much of the Aegean, including the Cyclades, Dodecanese, Sporades, and Crete, highs of 38–39°C are anticipated — especially from Sunday onward.
Fires Risk at Highest Level
The General Secretariat for Civil Protection has issued a Category 3 fire risk warning — the highest level — for Sunday, August 23. This applies to large swaths of mainland and island Greece, including Attica, Central Greece, the Peloponnese, parts of Macedonia and Thrace, and nearly all Aegean and Ionian islands.
Specific high-risk zones include Boeotia, Euboea, Evros, Rodopi, Thessaloniki, Chalkidiki, Mount Athos, Arta, Agrinio, Pyrgos, Trikala, Larissa, Magnesia, Karditsa, and the entire island of Crete — among many others.
Wind Shift from Monday
A dramatic shift begins Monday: strong meltemi winds will sweep across the Aegean Sea, reaching up to 7 Beaufort — with gusts potentially higher. These northerly winds will persist for at least two days and may further elevate fire danger by accelerating fire spread, even as they bring some modest cooling to coastal areas.
A slight temperature drop is expected Thursday and Friday — but it will come alongside powerful winds of up to 8 Beaufort, adding complexity to firefighting efforts and maritime operations.