Strong winds and heavy rainfall led to roads being flooded and traffic being disrupted in some parts of the country in the early hours of Friday.
According to reports, three tornadoes hit the island of Zakynthos, in the Ionian Sea, causing damage to homes and stores.
In the prefecture of Xanthi, northern Greece, a train en route to Thessaloniki was derailed though no injuries were reported.
Meanwhile, several homes and businesses flooded in a number of northern Athenian suburbs.
A tornado also caused damage in the broader area of Katakolo, in the Peloponesea, while roads flooded in ancient Olympia.