Take a look at the page below on the World Cruising and Sailing Wiki. We were in Mykonos Marina in September 2011 and completely revamped the entry, so it's probably as up to date as you'll find (although knowing Greece there may be one or two fewer mooring lines now). As for the meltemi, there's certainly less risk of a really strong one in late September but northerly winds still predominate.
Mykonos Marina - a Cruising Guide on the World Cruising and Sailing Wiki
ATHENE OF LYMINGTON
Athene of Lymington
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