The mountains of Greece and the Balkans are part of a mountain chain that runs across Europe and Asia, as far as south China and is of relative young age.
Some 250 million years ago, when Europe and Asia were separated from Africa by the shallow Tethys ocean, thick layers of limestone were formed. Around 60 million years ago, Africa and Europe began to move towards each other. Through these movements, mostly limestone, mountain chains were formed. Limestone mountains stretch from north Dalmatia to the Peloponnese and Crete. They are hard and slow to erode, and often exist as steep jagged escarpments through which steep sided gorges and canyons are cut by rivers. The absence of permanent ice during the ice ages has helped in the survival of many tertiary species of plants , like Ramondas, Haberleas and Jancaea heldreichii.
Contact with the flora of the east was greatly reduced and isolation resulted in the disappearance of many species, while at the same time the evolution of new species began with the colonisation of new environments. Also the contact with the west increased through similarities of climate and terrain. Not all of the new formed mountains are jagged. Like the Pindos highland areas, where slopes are moderate and summits are rounded. This region also has isolated serpentinite mountains like Mt Smolikas, or metamorphic rocks like on Mt Kajmaktcalan.
In Greece winter temperatures in the interior are low. Frost and snow occur frequently in northern Greece. By contrast the coasts are mostly frost free. The western coast of Greece has a warmer winter climate, rainfall is between 500 and 900mm which is more evenly spread throughout the year. The eastern coast and the Aegean islands have a more drier climate, there is little or no summer rainfall. Winters are correspondingly cooler. Enclosed basins inland may become much colder in winter, and built up heat in summer. The Aegean islands and Crete have the same kind of climate but are more equable, being tempered by the surrounding seas.