Those perfect blue skies of the traditional Greek islands postcards.... yes, they are actually quite true of the summers out here!
From April to October, the wonderful Mediterranean summer gives us brilliant sunshine all day long, almost every day. A great vacation factor, and none more so than when you are living on a boat!
In April, we can still get some cloudy days in the first couple of weeks; ditto with the latter part of October. The best times to sail in Greece would be from late April to early Oct. It's still possible to sail here until end of Oct; but one needs to be prepared for some not-so-sunny days.
More about the wind and weather ...
WIND The "meltemi" (summer winds) traditionally start around mid July, blow at their strongest in August (25-30 knots), tailing off during Sept. In reality, the meltemi can start any time in June - like most things Greek, it is unpredictable ! :) It's one consistency, a real bonus for us sailors! is direction: in the Dodecanese, it blows reliably from the NW. (In the mid-Aegean, it is N, in the western islands, NE). Not so conveniently, it does NOT follow the pattern which one often reads of: afternoon breezes and calm at night: it can blow at any time. It's pattern tends to be to blow strongly for 3-4 days, then die for a couple of days; then the cycle continues. Early and late in the season, there tend to be more relatively calm patches, the windier days becoming more common in midsummer.
TEMPERATURES: Daytime temperatures at the start of the sailing season (late April / early May) are around70-75F; lovely for sunbathing in a sheltered cove, a trifle chilly for bikinis on deck when it's windy. It warms up very fast during early May, however; to reach early 80's in late May/early June. The hottest time is August, temperatures of 85-90F. However, it is a very dry heat, and there is always a cooling breeze in the islands, so it is rare to feel TOO hot when on the water.