Greece in September or October?
 

I am considering going to Greece, the mainland and the Peloponnese only, in September or October. I've checked weather stats, but does anyone have an opinion on when is the better month to go? I have a free week off in September and am leaning in that direction, but I would appreciate any thoughts.

On the mainland- September

September is much better weather-wise. It'll be warmer and less windy. The sea will still be nice and comfortable for swimming. Evenings won't be as cool as they are in October.

We visited the north-western Greek mainland last September - Delphi, Meteora and Zagoria for a week, followed by a 2nd week on Lefkada. We arrived in Greece on 21st September and had very mixed weather, some warm sunshine but also rain and tremendous thunderstorms.

The weather can be lovely at that time of year but isn't guaranteed - we were told that the weather had broken down early last year and have had much better weather at that time of year on previous visits. I'd go as early as you can and head south.

Early September, weather almost guaranteed. Mid September through October is usually still good here on the Peloponnese, but expect some cloud cover & rain showers, still plenty of sun though.
Last year was crazy, the 2nd half of September much colder & wetter than usual, but October (& much of November) was much hotter than usual! We went swimming in the sea on 1st Nov & it was exceptionally warm.