The passage of the severe weather system named Byron has so far been intense, affecting the whole of Greece and causing significant problems.
According to the updated Emergency Bulletin of Dangerous Weather Phenomena issued by the National Meteorological Service (EMY), the heavy rains and storms affecting most regions, primarily in the eastern and southern parts of the country, are expected to continue until the early morning hours of Saturday.
School Closures: Schools will remain closed today, Friday, in Attica and many other regions across the country.
Traffic Disruption (Athens-Corinth Highway Closed): On Friday morning, the Athens-Corinth National Highway was closed from the Elefsina tolls heading toward Corinth due to landslides and accumulated water.
Flooding Hotspots: Significant problems are being reported in areas like Megara, Nea Peramos, and Mandra. The heavy rainfall has led to flooded roads and, in several areas, falling trees.
Σοβαρά⚠️ πλημμυρικά φαινόμενα στη νέα Πέραμο
Καμιά άσκοπη μετακίνηση σε νέα Πέραμο Μάνδρα Μέγαρα pic.twitter.com/9K6ji0b56b
— Forecast Weather Greece (@ForecastGreece) December 5, 2025
Emergency Alerts (112): Overnight from Thursday to Friday, repeated 112 warning messages were sent out in both Attica and other regions.
In the early hours of Friday, residents of Megara and Mandra received a 112 message instructing them to move from basements and ground floors to higher floors due to developing flood phenomena.
Flooding and road closures on Zakynthos due to weather system Byron
Intense rainfall since early this morning has caused significant issues in Alykes, Zakynthos, where roads are completely flooded. Local authorities are strongly urging citizens to avoid unnecessary travel.
The provincial road connecting Zakynthos and Alykes is closed from Mantolato southward due to heavy flooding. Issues were also reported on the provincial road near the village of Koukesi.
Following the cancellation of the 09:45 service from Zakynthos to Kyllini and the 11:45 return due to the severe weather, the shipping company has advised that all subsequent ferry crossings to and from the island are expected to operate normally.
112 alerts issued in Laconia
Two 112 emergency messages have been sent to residents in the Laconia regions of Eastern Mani and the Municipality of Evrotas, warning of landslides and heavy rainfall.
Residents are advised to limit travel to only essential journeys. The Fire Service has reportedly intervened twice to safely evacuate individuals.
⚠️Σοβαρά πλημμυρικά φαινόμενα στην περιοχή Βαθύ Γυθείου. pic.twitter.com/wACgwaTxKW
— Forecast Weather Greece (@ForecastGreece) December 4, 2025
Villages around Gytheio are experiencing particularly difficult conditions, with flooded roads and homes, crops, and agricultural machinery submerged in water.
The most severe problem in the region is reported on the Sparta – Gytheio National Road, where traffic has been completely interrupted. The road surface is flooded in multiple spots, making passage impossible and dangerous. Traffic is temporarily being redirected via alternative routes.
⚠️ΑΝΑΚΟΙΝΩΣΗ⚠️
Ενημερώνουμε τους πολίτες ότι έχει τεθεί απαγόρευση κυκλοφορίας οχημάτων στον οδικό άξονα Σπάρτη – Γύθειο, λόγω των πολλών πλημμυρισμένων σημείων που έχουν εντοπιστεί κατά μήκος του δρόμου.
Παρακαλούνται οι πολίτες να αποφεύγουν pic.twitter.com/lFlh8bAnkK
— Forecast Weather Greece (@ForecastGreece) December 4, 2025
Significant problems are also noted near the city of Sparta, particularly in Kladas, where anti-flood barriers have been placed due to the large accumulation of water.
School closures on Rhodes
Due to the intense weather phenomena, the Mayor of Rhodes, Alexandros Koliadis, has decided to suspend the operation of all educational institutions (of all levels) and sports facilities across the island’s Municipal Units for tomorrow, Friday, December 5, 2025.
This closure also includes Preschool Education units, Special Education Schools, and other municipal facilities. In Lindos, torrential rains have already turned roads into torrents.
Weather system forecast: “Byron” to persist
The impact of “Byron” is set to continue, with strong rain and thunderstorms forecast through the morning hours of Saturday (December 6, 2025) across most of the eastern and southern parts of the country.
Friday, Dec 5 – Worsening conditions, “red alert” areas:
The weather system will affect most of the eastern country. Heavy rain and thunderstorms are predicted for:
- Central Macedonia, Thessaly, and the Sporades
- Eastern Aegean Islands (from Chios southward) and the Dodecanese
- Cyclades and Crete until noon
- Eastern Central Greece (including Attica) and Evia until noon
- Eastern and Southern Peloponnese until the morning hours
RED WARNING: Phenomena are expected to be particularly severe and potentially dangerous (Red Warning) in the regional units of Pieria, Imathia, Chalkidiki, Thessaloniki, Thessaly, the Sporades, Evia, the Eastern Aegean Islands, and the Dodecanese.
Saturday (Dec 6)
Heavy phenomena are expected to weaken in most areas from the morning hours and will become limited primarily to the Dodecanese region.
