Sea surface temperatures across the Aegean and Ionian Seas have reached unusually high levels for June, according to the National Observatory of Athens. Current readings show temperatures between 20°C and 22°C (68–71.6°F), significantly exceeding seasonal norms.

The Ionian Sea is showing temperatures about 2°C (3.6°F) higher than average, while the Aegean sea temperatures are even higher, at 2-3°C (3.6-5.4°F) above average.

In the Ionian Sea, temperatures are approximately 2°C (3.6°F) above average. The Aegean Sea is experiencing even higher anomalies, with surface waters measuring 2–3°C (3.6–5.4°F) above typical values for this time of year. Experts from meteo.gr, the Observatory’s meteorological division, explained in a Facebook post that this warming trend is due not only to ongoing climate change but also to an extended period of calm weather, which has limited the usual flow of cooler northern air over the region

Highest Greek Sea Temperatures Ever Recorded

Greek waters saw their highest recorded temperatures in four decades during the summer of 2024, with surface and upper ocean layers exceeding 28°C (82.4°F).

Between 1991 and 2020, the average temperature of Greek seas rose by 1.5°C (2.7°F), with the most significant warming observed in the northern Aegean, the Ionian Sea, and around Crete—at an estimated rate of 0.08°C (0.144°F) per year.