Greece has a warm Mediterranean climate. Summers in the lowlands are hot and dry with clear skies. The mountain areas are much cooler, with considerable rain in winter. The weather in the Greek Islands is generally beautiful with cloudless blue skies, especially in summer.

Summer weather in the islands begins in May with daily highs in the mid-20s. By July the daytime temperature is often in the 30s. July and August are the peak summer months, and temperature will rarely drop below 20°C even at night. On occasion when the air is calm the daytime heat can be oppressive inland or in a large town such as Athens. Fortunately the islands are relieved by the cooling "Meltemi" winds - sea breezes that blow from the north and north-west.

The winds are strongest in July and August when they are needed the most. Mid-May to Mid-September is very dry, while July and August are unlikely to see any rainfall at all. Winters are mild and wet - somewhat akin to an English spring. Temperature will generally be in the low to mid-teens, although a sunny day can sometimes see the temperature creep up towards 20°C.

During the summer months and especially between mid July and mid August, strong winds are common in the Aegean Sea. These winds are called "Meltemi" and blow from North/Northeast. "Meltemi" starts suddenly and can blow continuously for several days. Wind conditions in the Ionian are generally 1-2 beaufort less than in the Aegean.

	North Aegean	Middle Aegean	South Aegean
April-May	N to NW 4	N NW 5-6	N NW 5-6
June-midJuly	NW N NE 4-5	NW 4-6	NW W 5-7
midJuly-August	N NE 5 (6)	N NE 5 (6-7)	N NW 5 (7-8)
Sept.-October	N NE 3-5	S SE 5-6	S SE 5-6
(during "Meltemi" period)

The Meltemi wind was known by the old Greek as the Etesian northern winds, and results from a high pressure system (>1025) laying over the Balkan/Hungary area and a relatively low pressure (<1010) system over Turkey. Although this katabatic wind can bring about harsh sailing conditions it also provides cooling, low humidity and good visibility. Furthermore, it can be characterized as one of the few Mediterranean winds that do not necessarily die out at the end of the day and can easily last more than three to six days. The onset is the monsoonal effect of the summer season that leads to the development of an intense heat trough over southern Asia extending westward over the Anatolian plateau. Higher pressure dominates over the relatively cooler surface of the Mediterranean Sea, and settled, dry weather persists. Northerly winds prevail along the Greek coast during the winter also, but only those northerly winds occurring between May and November are considered Etesian. The pressure gradients necessary to drive the Meltemi result from a combination of:

• The monsoonal effect during the summer that leads to a low pressure trough over Turkey. Etesian winds flow from a high pressure ridge over the Balkans toward the trough. During a strong Etesian, the trough may extend relatively far to the west and beyond Rhodes. It may also form a closed low, resulting in almost calm winds at Rhodes.
• Synoptic conditions leading to anti-cyclogenesis over the Balkans.
• A jet-effect wind increase caused by channelling of the wind between islands and mountain valleys. These effects tend to render wind reports from certain locations unrepresentative. In the lee of Crete, katabatic flow off the mountains generates gusty winds similar to the Fφhn of the Alps. The mountain valleys tend to channel the flow which increases the wind velocity.

Usually blows with force up to 7 during the afternoon and slows 1-2 force or dies after sundown.

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