The climate in Greece is typical of the Mediterranean climate: mild and rainy winters, relatively warm and dry summers and, generally, extended periods of sunshine throughout most of the year.
Greece is situated at the most southeastern part of Europe, located between the 34° and 42° parallel N., with a meridional extent from 19° to 28° E. and borders the Aegean Sea, the Ionian Sea and the East Mediterranean Sea. The climate in Greece is typical of the Mediterranean climate: mild and rainy winters, relatively warm and dry summers and, generally, extended periods of sunshine throughout most of the year. A great variety of climate subtypes, always within the Mediterranean climate frame, are encountered in several regions of Greece. This is due to the influence of topography (great mountain chains along the central part and other mountainous bodies) on the air masses coming from the moisture sources of the central Mediterranean Sea.
Thus the weather in Greece varies from the dry climate of Attiki (Athens’ greater area) and East Greece in general, to the wet climate of Northern and Western Greece. In climatological terms, the year can be broadly subdivided into two main seasons: The cold and rainy period lasting from mid-October until the end of March, and the warm and dry season lasting from April until September.
During the first period the coldest months are January and February, with, a mean minimum temperature ranging, on average, between 5 -10 degrees Celsius near the coasts and 0 – 5 Celsius over the mainland, with lower values (generally below freezing) over the northern part of the country.
Long stretches of consecutive rainy days are infrequent in Greece, even during the winter, and the sky does not remain cloudy for more than a few days in a row, as it does in other regions of the world. “Bad weather” days in winter are often interrupted, during January and the first fortnight of February, with sunny days, known as ‘Halcyon days’ since ancient times. The winter is milder in the Aegean and Ionian Islands compared to Northern and Eastern mainland Greece. During the warm and dry period the weather is usually stable, the sky is clear, the sun is bright and there is generally no rainfall. There are, however, infrequent and brief intervals of rapid rain or thunderstorms chiefly over mainland areas.
The warmest period occurs during the last ten days of July and the first ten days of August, when the mean maximum temperature lies between 29.0 and 35.0 degrees Celsius. During the warm period the high temperatures are tempered by fresh sea breezes in the coastal areas of the country and from the north winds, known as ‘Etesian’, blowing mainly in the Aegean

Northern Greece Climate
Northern Macedonia and the northern part of Epiros have a climate similar to the Balkans, with freezing winters and very hot, humid summers. Attica’s peninsula, the Southern Aegean Islands and the central and eastern Peloponnese have a typically Mediterranean climate with hot, dry summers and milder winters.
Snow covers the highest mountains during the winter, while the temperatures soar to 40°C (104°F) during July and August. During these months the meltemi, a strong northerly wind, sweeps the eastern coast of mainland Greece and the Aegean islands. The areas more to the south and to the west do not experience the meltemi.

Southern Greece Climate
Crete stays warm the longest - you can swim off its southern coast from mid-April to November. Mid-October is when the rainy seasons starts in most areas, and the weather stays cold and wet until February, although there are also occasional winter days with clear blue skies and sunshine.