The Weather in Athens
Nice weather is a way of life for the Greeks, boasting over 300 days of sunshine a year. April, May and June, September and October are probably the best months to visit weather-wise.
This is the best time to visit sites such as Delphi, Olympia, Vergina ...etc as they are less crowded, as with anywhere in Greece at this time. You may get a day or two of rain but nothing which will spoil your holidays.
Cooler weather can be found from November to March but there could also be days when you can sit outside comfortably, without even a coat. Athens is lively during these months with plenty of night life . It does snow in Greece but not more than twice a year in Athens or the islands. It's so rare that it is a major event. However, it does snow in the mountains, so much that you can ski there.Keeping up with their tradition is something which the Greeks are especially proud of and visiting Greece at Easter time is an experience. It usually falls in April and being spring everything is in bloom and the smell of lamb roasting fills the air. Easter, and the 15th of August are the biggest holidays in Greece. The days preceding and following these holidays are the worst times to be traveling around Greece but, it is also the best time to be in Athens because the city will be empty.
with the SKIRON
Forecast for Greece based on UTC NCEP Analysis
Surface Observations over Greece .
The most recently observed weather conditions for Greece are available here.