The weather in Greece is expected to deteriorate rapidly with heavy rain and thunderstorms forecast from tonight until Sunday evening (September 28, 2025) in the Ionian (Zakynthos, Kefalonia, Ithaca, Lefkada), Aetolia-Acarnania, western Peloponnese (Achaia, Ilia, Messinia), and the southern parts of Epirus (Arta and Preveza), according to the updated severe weather warning issued by the Hellenic National Meteorological Service (HNMS).

According to a post by former HNMS director Thodoris Kolydas, in the coming hours, the low-pressure system will begin to affect Greece, bringing localized severe thunderstorms, mainly in parts of western Greece, both on the islands and in the mainland areas.
In more detail, the specific regions across the country expected to be affected today:

ATTICA

Weather: A few clouds, increasing locally in the evening.

Winds: Northerly to northeasterly 5–6 Beaufort, locally 7 in the east, easing from midday.

Temperature: 15–25/26°C.

THESSALONIKI

Weather: Clouds, occasionally increased.

Winds: Easterly directions 3–5 Beaufort, easing from the morning.

Temperature: 15–23/24°C.

MACEDONIA, THRACE

Weather: Clouds, at times increased, with occasional showers in western and central Macedonia.

Winds: East-northeasterly 3–5 Beaufort, locally 6 in the east, easing from midday.

Temperature: 14–24°C, 2–3 degrees lower in western Macedonia.