This is not autumn as most foreigners imagine it. September in Greece is still summer in all but name. The meltemi winds (the strong, dry northern winds of the Aegean) begin to subside. Sea temperatures peak, often warmer than in July. Tourists thin out after the first week, but the sun remains intense, temperatures frequently reach the high 20s°C (mid-80s°F), and swimming is sublime.

On a technical, calendrical level, autumn in Greece runs from the autumnal equinox (around September 22nd or 23rd) to the winter solstice (around December 21st or 22nd) . However, to ask “when is autumn in Greece” is to ask a question about experience , not just astronomy. Unlike the sharp, crisp transition of Northern Europe or the rapid leaf-drop of New England, Greek autumn is a long, slow, and deeply textured season—arguably the country’s most beautiful and complex. The Three Distinct Phases of Greek Autumn Autumn in Greece does not arrive uniformly. Instead, it unfolds in three distinct acts, dictated more by geography and ancient weather patterns than by the calendar.

To experience Greece is to experience its autumn. It is the season of nostalgia (from nostos – return home, and algos – pain/longing), the bittersweet, beautiful turning of the year. Do not come for the summer. Come for the autumn.

If you want the deep, experiential answer:

Meteorological truth: True autumn has not yet begun. This is a liminal month—the "second summer" ( Allou genitsa in folk tradition). The only hint of change is the shortening daylight and the first, rare, dramatic thunderstorms that break the four-month summer drought.