An emergency weather warning for severe weather featuring rain, thunderstorms and lightning lasting 24 hours was issued by the National Meteorological Service (EMY) on Monday afternoon.

According to the EMY’s emergency bulletin, “a deterioration in the weather is forecast from the early hours of Tuesday (September 22, 2026) until the early morning hours of Wednesday (September 23, 2026) in the wider northwestern Aegean region, with heavy rainfall and localized thunderstorms, temporarily accompanied by frequent lightning strikes, while there is also a possibility of localized hail.”

The 4 Areas That Will Be Affected

Regarding the areas that will be affected, the EMY clarifies that locally heavy rainfall and thunderstorms are forecast:

• On Tuesday (September 22, 2023)
• a. In Thessaly (Magnesia regional unit, mainly offshore and coastal areas) from the early hours.
• b. In the Sporades and Halkidiki from the early hours until the afternoon.
• c. In Evia (mainly central and northern areas) from the morning hours until the afternoon.
• On Wednesday (September 23, 2026)
• a. In Thessaly (Magnesia regional unit, mainly offshore and coastal areas) until the early morning hours.

Tsatrafyllias: Sudden Autumn Shift with Storms and Temperatures Plunging by Up to 8 Degrees

As meteorologist Giorgos Tsatrafyllias said in his forecast for protothema.gr, the week begins with increased atmospheric instability and temperatures that are high for the season.

However, from Tuesday, the weather will change abruptly, bringing an intense autumnal shift, with rain, thunderstorms and a noticeable drop in temperatures, locally reaching as much as 8 degrees.

More specifically:

For today, Monday (September 21), initially clear skies are expected. After midday, however, cloud cover will develop over the Ionian and mainland areas, bringing brief showers or rain showers, mainly in mountainous areas.

Temperatures will reach 32 to 33 degrees in mainland areas, 30 degrees in Crete and the Dodecanese, and 28 degrees in the eastern Aegean and the Ionian.

The winds over the seas will be mainly northerly, reaching up to 6 Beaufort in the Aegean and up to 5 Beaufort in the Ionian.

In Attica, there is a chance of light rain after midday. Temperatures will range from 17 to 31 degrees, while winds will be light.

In Thessaloniki, no significant rainfall is expected, although there is a chance of a few light showers around midday. Winds in the Thermaic Gulf will be light, while the maximum temperature will reach 32 degrees.

The Weather in the Coming Days

On Tuesday and Wednesday, an atmospheric disturbance moving in from the northwest will bring rain and thunderstorms, initially to the Ionian, Epirus, Macedonia and Thessaly, and gradually to Central Greece, Evia, the Sporades, the Peloponnese, the Cyclades and Crete. The phenomena will be locally strong, particularly in eastern and southern Greece.

At the same time, northerly winds over the seas will strengthen, reaching 7 Beaufort, while temperatures will drop significantly, locally by as much as 8 degrees, and will not exceed 25 to 26 degrees. During the evening hours, temperatures could even fall into single digits in mountainous areas.

On Thursday, the weather phenomena will cease across the country and temperatures will begin to rise.

Finally, according to the latest forecast data, on Friday and over the weekend, temperatures will remain close to seasonal averages, winds will strengthen, while the development of rainfall will depend on the path of the low-pressure system expected to form over the central Mediterranean. More time is needed before safer conclusions can be drawn.