A Mediterranean climate resembles the climate of the lands bordering the Mediterranean Sea. It can be observed in different regions of the world, in particular there are five of them. Each of five Mediterranean climates lies within 30°-45° latitude, with the exception of the Mediterranean Basin itself. It is situated the most northerly, and due to the east-west mountain ranges that are to its north, form the specific shelter extending the "Mediterranean effect". In total, these 5 areas comprise only about 2% of the earth's landmass.
The largest of them is the Mediterranean itself, about 60% of the world's Mediterranean climate. South and Western Australia takes the second place, which together equal about 22%. The remaining three, from largest to smallest respectively: California (10%), Chile (5%), and South Africa (3%). The most interesting fact that is worth of mentioning is that this last and smallest Mediterranean climate is the richest of the 6 floristic kingdoms of the world, with a density of 1,300 species/10,000km2! It contains over 80% of the plant species found in the entire Mediterranean climate region!
The Mediterranean climate is a special type of climate that describes a regime of hot summer drought and winter rain in the mid-latitudes, north of the subtropical climate zone. Areas with this climate receive almost all their rain during the winter months, and may go 4-5 months during the summer without having any precipitation. As an example, San Francisco in California, USA, has an average of 448 mm (17.6 in.) of rain from November through April each year, but averages only 52 mm (2 in.) of rain for the rest of the year.
This phenomenon can be explained by subtropical high pressure cells that dominate during summer and are thus equivalent to deserts from the point of view of air mass positions. As for winters, the polar front brings weather conditions similar to those of an oceanic climate, with frequent precipitation.
Due to the close proximity to large bodies of water Mediterranean temperatures are generally moderate with a relatively small range of temperatures between the winter low and summer high (although the daily range of temperatures during the summer is large, except along the immediate coasts).
Summer temperatures are rather variable depending on the region while winter temperatures remain almost the same (rarely reach freezing except in areas with a high elevation) in all regions with the Mediterranean climate. The difference of summer temperatures can be seen best of all by the example of Athens, Greece and San Francisco, California. The former experiences rather high temperatures in the summer, while the latter has cool, mild summers due to its proximity to the open Pacific Ocean. In the summer, the temperatures range from mild to very warm, depending on distance from the Open Ocean, elevation, and latitude.
Inland locations that are not affected by the sea breezes can experience severe heat during the summer as inside the Sacramento Valley of northern California. The average summer temperature resembles summer temperatures characteristic of hot deserts (often around 40 °C or 100 °F), although winters are rainy enough to allow lush vegetation that is untypical for deserts.
Areas that experience the common Mediterranean pattern of cool, rainy winters and very dry summers, but which experience milder average summer temperatures include, Porto, in Portugal and San Francisco, in California.
The "temperate Mediterranean" climate, that is characterized with somewhat colder winters and more distinct seasons, is most evident in northern Italy and Greece, as well as southern Oregon. This can be explained by being cut off from milder ocean winds and the slightly higher latitude.
Being adjacent to locations with Mediterranean climates, some areas of high altitude may have the cold winters that are the characteristic of a continental climate.
This mix of desert-like summer weather and cool rainy winters results in the unusual mix of biological life. The Mediterranean climate zone tends to coincide with the biome known as scrub forest or chaparral, characterized by small, drought-resistant shrub and tree species.
Well, you may not know enough to consider yourself a weatherman, but at least you know a little about the Mediterranean and Mediterranean climates.