In both the northern and southern hemispheres all areas with Mediterranean-type climates are on or close to the 35° latitude lines and bordering the sea (Grove & Rackham 2003: 11 and fig. 1.2). Ancient Greek settlement in fact ranged somewhat beyond the fringe of land surrounding the Mediterranean Sea. Mediterranean climates are characterized by relatively mild, wet winters and hot, dry summers. Except in the high mountains, few areas suffer from intense and regular frosts. Often the limits of the olive’s cold tolerance are perceived as defining the extent of Mediterranean zone, though this is something of an over-simplification (Grove & Rackham 2003: 11). Certainly it is true that the olive and Greek culture have flourished in most of the same places.
Summers are largely sunny with temperatures often over 30 degrees C, and in many areas at altitudes under 200 m above sea level even dew is rare. This is wonderful for the modern tourist trade, which can usually guarantee its customers a vacation uninterrupted by rain, though humidity can be high in locations close to the sea, but it places severe constraints on other kinds of human activities. Summer temperatures are generally cooler at higher altitudes, and places only a few kilometres distant from each other but differing by several hundred metres in altitude can also differ perceptibly in temperature.
Precipitation in the Mediterranean is characterized by its unpredictability, and this has important implications for agriculture in the region. Generally the bulk of the year’s rainfall occurs between mid-September and April and rainfall events may be very unevenly distributed over this time. Even over the summer, occasionally a sudden, violent thunderstorm may result in flash floods or damaging hailstorms. In addition, rainfall in any particular area may vary dramatically from year to year. And, often over short distances, especially over changes in altitude and aspect (the direction a place faces and to which it is exposed), rainfall can vary quite substantially from one place to another. Generally, precipitation increases (and the length of the dry season decreases) with altitude. West-facing locations such as the island of Kerkyra (modern Corfu) are usually wetter than east-facing ones such as the peninsula of Methana in the Saronic Gulf. Absolute amounts of annual precipitation rarely exceed 1,000 mm except in the more northerly parts of the region, and at high altitudes. In most parts of southern Greece, Italy and Spain average annual rainfall ranges from 400 to 650 mm, though in some significant places this figure is lower. Athens averages 385 mm per year, Thera (modern Santorini) 357 mm, close to the limits for unirrigated cereal cultivation (Grove & Rackham 2003: 24-8).
World History
