having a tough time determining what the weather will be like in early october in athens, greek islands and istanbul.
are we talking sunny and 70's or is it typically alot cooler?

My only problem with October on in the Mediterranean is for island hopping. You can have beautiful weather, but rough seas crop up and some hydrofoils don't run. It makes planning difficult.

I've had several holidays in various parts of Greece on late September to early October. The weather has usually been sunny and warm, mid 20s C, warm enough for the beach most days but a bit cooler in the evenings. We've had the occasional thunderstorm but nothing thats lasted more than a few hours or at most half a day out of a week.

thanks so much, that is very helpful! Do you mind me asking how late into october you were there?

The latest I've been in Greece was returning home from Rhodes on 15th October. I seem to remember it was starting to get a bit windy by then. We were in Kalymnos and Kos for 2 weeks until 10th October in 2004 and had one cloudy, windy and cool day out of the whole 2 weeks.

I've been in the islands in early to mid October. Didn't plan on weather as cool as we had--60's high for the day and 50 at night or so- -let's just say I wore that one turtleneck ALOT. Maybe had 70's during the day on a couple of days, but nights called for turtleneck and jacket. Had a little rain, alot of sun. Some of the islands are effectively "closed" by that time.

It does of course depend on which islands you visit. The Ionian islands can turn changeable sooner. Many of the more popular islands stay "open" until the late October half-term school holiday.