Greece’s Meteorology Service has issued a bad weather warning with strong rainfalls, thunderstorms, winds up to 9B & snowfalls in mountainous areas!Weather deterioration is expected to be of short duration and come from the West.
Sunday, Nov 26/2017: As of the evening: the Ionian Sea and islands, Epirus, and West Sterea, North-west Peloponnese and the Dodecanese in Eastern Aegean Sea.
Monday, Nov 27/2017:
In the morning hours: Ionian Sea, Epirus, West Sterea and possibly West Macedonia.
Snowfall is expected initially on the mountains of Epirus & Macedonia (above 600 meters) and gradually on the mountains of North Greece and Thessaly.

For the time being, Saturday, 4 pm, the weather in Athens is pleasant, with sunshine and 19 degrees Celsius. Rain expected in Athens too as of Sunday afternoon.