In July and August things get hotter. You will probably meet a (kafsona) heat wave in most of the Greek cities in the South. Also it's more crowded and rooms are harder to find. Athens and the Northern mainland can be hot in the day but mornings and late afternoons are fine.

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.