Temperature-wise, September is almost as warm as August, especially earlier in the month. The daytime averages hover around 75°F (24°C) which is about six degrees cooler but certainly still warm enough to be outside. In fact, it's sometimes even more pleasant than August because the cooler temperatures help the midday heat feel more bearable.
The first and middle parts of the month see almost no precipitation. Toward the end of September, moderate rains begin but they're still light and not every day by any means. The whole month gets only three days of rain total, which mostly manifests as scattered showers. Best of all, the water temperature at the beaches is still about 75°F (24°C).
For more on weather this month, see Greece in September: Travel Tips, Weather, and More.
Crowds and Costs
The beauty of September lies in the dramatic falloff in crowds. While August can sometimes feel like a zoo at the major tourist sites, September is much more subdued. There are still people around—it's not like wintertime when the crowds completely disappear—but it's nothing like the height of summer when you can barely turn around without bumping into people.
Another great thing about visiting Athens in September is that some places begin bringing prices down. You won't see low-season rates yet but hotels and airlines both begin offering discounts.
Where To Go
There's almost nowhere in the city that isn't completely wonderful in September. The atmosphere is pleasant, it's sunny outside, and most of the summer tourists have left. For people who are interested in Greek history, it's an exceptional time to check out the Acropolis which will have pleasant temperatures and far fewer people. It's also a great time to explore the laiki markets and other outdoor spaces, checking out the food stalls and wandering into little shops. Restaurants and tavernas are often running specials this time of year, too.
If you have a hankering to get out of town, try taking a day trip to the Attica wine region or head to the Athens Riviera to check out Cape Sounion and the Temple of Poseidon. Farther north, you can visit Delphi which is home to the Sanctuary of Apollo, once thought to be the center of the world.
It's also a fantastic time to head to the beaches, as the water is still warm and the air temperature is great for sunbathing. Check out the turquoise water of Anavyssos south of town or Karavi at Schinias to the north, both of which can be reached in less than an hour by vehicle. You can also hop out to one of the islands for a weekend getaway. Santorini, Mykonos, Crete, Paros, and others will still be open and full of things to do.
What to Do
One of the first stops you make in Athens should be at the Acropolis, regardless of the time of year. The ancient citadel features some of world's most famous structures including the Parthenon and the Propylaia. Walk through ruins such as the Erechtheion, Hadrian's Library, and the Temple of Athena Nike. It's also a great time of year to visit museums since you won't have to wait in such long lines. Try checking out the Museum of Cycladic Art or the Byzantine and Christian Museum.
If you make it over to the Attica wine region, drop by the Strofilia Estate or the Papagiannakos Winery where you can sip local blends in their tasting room. Or, if you'd prefer to tour multiple vineyards, take a tour with Attica Wine and Food Experience (AWAFE) which operates wine-tasting trips, as well as those paired with gastronomy, history, and culture.
On the beaches, you can go snorkeling or take a sailing trip to Aegina Island. There are cruises to the Saronic Islands, cliff-diving boat trips to Cape Marathon, and yacht trips along the Athens Riviera. You can also take a ferry out to any of the famous islands like Santorini, Mykonos, or Crete. Just keep in mind that for the latter, some quit operating or slow down toward the end of the month so plan ahead.
Events in September
Armata Festival (changes dates): Every September, Spetses Island hosts a festive celebration that commemorates a naval battle between Spetses and Kosta in the early 19th century. Boatbuilders gather a week before the festival to make an impressive wooden boat effigy and on the final day, there's a battle reenactment and fireworks.
Athens International Film Festival (changes dates): The Athens International Film Festival is a huge cinema event that happens every September and involves film screenings at multiple theaters throughout the city. Among other honors, the festival awards the City of Athens Best Director Award and the The Golden Athena Award.
Traveling to Athens in September? Check out this great itinerary.
Highlights of Athens - 5 Days. If you'd rather have the arrangements taken care of for you, this five-day tour of Athens is a fantastic way to explore the city without the hassle of planning anything out. Among numerous highlights, it includes a visit to the Acropolis and a food tour of the city's markets. Additionally, participants visit the Temple of Poseidon in the Athens Riviera.
Adventurous Athens, Central Greece, & Corfu - 7 Days. This weeklong adventure trip takes you through some of the highlights of central Greece. Go up to Meteora's monasteries in the sky, then down into the gorges of the Pindos mountain range to explore the stone villages of Zagori. End your trip by kayaking around Corfu's petite Pontikonisi Island.