The Hellenic National Meteorological Service (EMY) issued an emergency weather bulletin at midday on Monday (30/3), with a “red” warning for 11 regions.

Specifically:
A weather system in the western Mediterranean, named Erminio (as designated by the Italian Meteorological Service – Central Mediterranean Group), is moving southeast and is expected to affect most parts of the country on Wednesday (01-04-26) and Thursday (02-04-26), bringing prolonged and intense rainfall and thunderstorms, possibly accompanied by local hailstorms.

On Wednesday (1/4), in eastern Greece, east-southeasterly winds of intensity 8 to 9 Beaufort, and locally up to 10 Beaufort in the Dodecanese area, are expected.

Heavy snowfall is forecast on Wednesday in the mountainous regions of Epirus and Macedonia.

A. Wednesday (01-04-26)

From this weather system, a surface low-pressure system is forming over Libya and moving rapidly north-northeast.

Heavy rain and thunderstorms are forecast:

a. In the Ionian Islands from the early morning hours (orange warning).

b. In eastern Peloponnese, eastern Central Greece, Euboea, Thessaly, and the Sporades from late morning until late at night (red warning).

c. In Attica from late morning until the evening (red warning).

d. In the Cyclades (mainly the northern parts) and the eastern Aegean islands (from Chios and southward) from the afternoon until late at night (orange warning).

e. In the Dodecanese from the afternoon (red warning).

B. Thursday (02-04-26)

Heavy rain and thunderstorms are forecast:

a. In western and southern Peloponnese from the morning hours until late at night (red warning).

b. In eastern Thessaly (regional units of Larissa and Magnesia, including the Sporades) from the early hours until midday (orange warning).

c. In the regional units of Central Macedonia: Pieria, Imathia, Chalkidiki, and Serres from the morning hours until late afternoon (orange warning).

d. In Crete (mainly western and southern parts) from midday until late at night (red warning).

e. In the eastern Aegean islands from late afternoon (orange warning).

f. In the Dodecanese during the early hours of the day (red warning) and again from late afternoon (orange warning).

Sunny skies with some clouds are expected today, Monday, March 30, according to the EMY forecast, but from Tuesday evening the weather changes significantly, with heavy rainfall, thunderstorms, and gusty winds up to 10 Beaufort. Meteorologist Yannis Kallianos warns of organized and strong bad weather with an increased risk of flooding in several areas, while Thodoris Kolydas points out that the development is associated with a double cyclogenesis in the Mediterranean, which may significantly enhance the dynamics of phenomena.

Intense weather on April Fool’s Day – Authorities on alert

Authorities are put on heightened alert, as according to meteorologist Yannis Kallianos, an organized and strong bad weather system will affect the country from Tuesday evening, with Wednesday, April 1, being characterized as the most aggravated day.

The first phenomena will appear from the afternoon and evening of Tuesday in the west, the north, and the islands of the eastern Aegean, with local rains that will gradually intensify.

On Wednesday, the low barometric pressure will be in full development over Greece, causing generalized and heavy rainfall. On Thursday and Friday, the phenomena will continue, but with less intensity.

The areas most at risk

According to Yannis Kallianos, the areas likely to face the most intense phenomena and possible flooding episodes are:

Eastern and southern Peloponnese, central and eastern Sterea, Attica, Euboea, Sporades, eastern, southern, and western Thessaly, central and eastern Macedonia, as well as areas of the eastern, northeastern, and southeastern Aegean.

The north-eastern and eastern parts of the Baltic Sea and the north-eastern and eastern parts of the Baltic Sea.

Gusty winds up to 10 Beaufort

Winds will be a key feature of the bad weather. On Wednesday, initially strong to gusty southerly winds will blow, which will gradually shift to northerly winds in the north, mainly in the northern Aegean.

The intensities will reach 8 to 9 Beaufort, while locally they may even reach 10 Beaufort.

Yannis Kallianos points out that the barometric low will draw a lot of energy from the sea. Although the probability of the formation of a “meteorological bomb” – i.e., a rapid drop in atmospheric pressure – is estimated at 25%, the situation is considered serious, as rainfall levels may exceed 100 mm within 24 hours in the most affected areas.

Meteorologist George Tsatrafillas disagrees with the term “meteorological bomb”, noting in a post that “next Wednesday 1/4 there are indications of a significant strengthening of a barometric low in our region, but without currently meeting the scientific criteria for its characterization as a “meteorological bomb”.

Kolydas warning – Caution in Thessaly

Meteorologist Thodoris Kolydas confirms the noticeable change in the weather from Tuesday afternoon, with increased clouds, local rain, and rainfall initially in the west and north and then throughout the country.

From Wednesday noon, sporadic thunderstorms are expected, while in the northern mountains, snowfall cannot be excluded.

He warns that Thessaly needs special attention, as the dynamics of the system appear strong, with high winds and phenomena.

Double cyclogenesis in the Mediterranean – How the dangerous system is being created

In a later analysis, Thodoris Kolydas explains that atmospheric evolution is linked to a particularly rare transport of cold gas masses from Europe to northern Africa, reaching as far south as Algeria and parts of the Sahel.

Temperatures in northern Africa could be up to 15 degrees below normal, with values close to 10 degrees Celsius instead of the usual 25 degrees.

At the 500 hPa level, an upper low is forming within the so-called “cold lake”, which is disrupting atmospheric circulation and may even cause rare rainfall in desert areas.

This cold stock, as it shifts from southern Algeria to Libya, may lead to the creation of a second barometric low, more critical for Greece.

Unlike the first central Mediterranean system, the second low will form near the coast of Africa, in an environment of intense heat gradients and strong dynamic support from the upper atmosphere.

If sufficiently organized, it will move towards the eastern Mediterranean carrying a large moisture load and creating conditions for intense and dangerous phenomena in our country.

In other words, the possible feedback of the system over North Africa is considered the key element that can significantly enhance the bad weather that will affect Greece in the coming days.

The temperature exceeded 20 degrees on Sunday, 29 March

The temperature in the country rose on Sunday, 29/03, with maximum values exceeding 20°C in some places. According to the network of automatic weather stations of the National Observatory of Athens / meteo.gr, the highest maximum temperature was recorded in Elefsina with 20.3 °C.

The map in the image below shows the distribution of the maximum temperature in the country and the 8 stations with the highest maximum according to 559 currently active stations.

Today’s weather

Improved weather is expected, with a few clouds, locally increasing at times. During the warmer hours of the day, isolated showers are possible in continental areas and in the mountains of Crete.

The temperature will range in Western Macedonia from 0 to 14 degrees Celsius, in the rest of Northern Greece from 3 to 17-19 degrees Celsius, in Epirus from 3 to 15-16 degrees Celsius, in Thessaly from 3 to 19-21 degrees Celsius, in the rest of the mainland from 6 to 17-20 degrees Celsius, in the Ionian Islands from 8 to 16-17 degrees Celsius and in the Aegean Islands and Crete from 7 to 18-20 degrees Celsius.

The winds will blow in the Aegean Sea west-northwest with intensities of 4-5 Beaufort and locally 6 Beaufort, but in the afternoon in the Central and North Aegean Sea, they will shift to south winds with intensities up to 5 Beaufort. In the Ionian Sea, the winds will blow northwest with intensities of 4-5 Beaufort.

In Attica, we expect a few clouds. The winds will blow mainly from western directions with intensities of 3-5 Beaufort. The temperature will range from 10 to 18-19 degrees Celsius.

In Thessaloniki, we expect a few clouds, denser during the warm hours of the day. The winds will blow from northwestern directions with intensities of 3-4 Beaufort. The temperature will range from 8 to 19 degrees Celsius.

The weather on Tuesday, 31-03-2026

A few clouds that will gradually increase, and in most areas, there will be local rain or rain, and in the southwest, from the afternoon, sporadic thunderstorms. The phenomena in the evening hours in the west, central, and south will intensify. Snowfall will occur in the continental highlands.
Snowfall will occur in the continental mountains.

Winds will blow south southeast at 4 to 6 Beaufort and gradually from the afternoon in the central and southern parts at 7 to 8 Beaufort.

The temperature will rise slightly towards the minimum values.

The weather on Wednesday, 01-04-2026

Clouds, partly cloudy with local rain or rain in the west and north, and gradually in the rest of the regions. Sporadic thunderstorms will occur after noon in the west and north, and snowfall in the northern continental mountains.

Winds will blow from southern directions up to 4 to 5 Beaufort.

The temperature will not change significantly and will reach 16 to 18 degrees in most parts of the country.

The weather on Wednesday, 01-04-2026

Bad weather with showers and thunderstorms in the west and south, and gradually in the central, northern, and eastern Aegean. The phenomena will be intense in places. Snowfall will occur mainly in the central and northern continental highlands, which will be dense in the north.

Winds from eastern directions, 6 to 8 and locally in the Aegean up to 9 Beaufort.

The temperature will drop slightly towards its maximum values.

The weather on Thursday, 02-04-2026

Clouds at times increase with showers and occasional thunderstorms in most parts of the country. Snowfall will occur in the continental highlands.

Winds in the north from eastern directions 5 to 7 Beaufort, in the rest of the regions south-southwestern 6 to 7 and locally 8 Beaufort.

The temperature will not change significantly.

The weather on Friday, 03-04-2026

In the eastern part of the country cloudy with rain and occasional thunderstorms, mainly on the islands of the eastern Aegean. In the rest of the country, clouds, partly cloudy with local showers. The phenomena will weaken from the afternoon hours.

Winds will blow from westerly directions 4 to 6 and in the southern seas up to 7 Beaufort, weakening from the afternoon.

From now onwards, the wind will blow from north to south-east and from the south to south-east from the south-east.
The temperature without significant change.