Mediterranean climate is a climate that resembles those of the lands bordering the Mediterranean Sea.

In the United States, the California coast Has a mediterranean climate.  Large population centers including greater Los Angeles and San Francisco have various Mediterranean climates.

Key characteristics of  Mediterranean climates for growers and gardners:

• Almost all rainfall is in winter months
• Summers are very dry
• Very mild winters
• Mild to warm summers
  

Many great garden plants and flowers come originally from Mediterranean climates.  A great example is the california poppy . These plants have beautiful golden blooms and thrive in other Mediterranean climates as well.

Many plants that do well in a  Mediterranean climate will thrive in other climates with a little help. For example, protecting Califorinia poppy plants from cold winter temperatures by bringing them inside.

 

From Wikipedia, the free encyclopedia

A Mediterranean climate is a climate that resembles those of the lands bordering the Mediterranean Sea. These climates generally occur on the western coasts of continental landmasses, roughly between the latitudes of 30° and 45° north and south of the equator.

Location of Mediterranean Climates

Besides the Mediterranean Basin, regions which have a Mediterranean climate include much of California between Cape Mendocino and greater Los Angeles, the Western Cape in South Africa, central Chile, the coastal areas of southern Western Australia and western South Australia.

Isolated examples of microclimates which approximate the Mediterranean climate may occur outside the Mediterranean climate zones, but these generally are a result of localized processes that are not characteristic of the Mediterranean climate regime.

Mediterranean climates on land tend to grade off poleward toward zones of oceanic or maritime climate in which summer rains are significant and equatorward into dry-summer steppes where the winter rains are inadequate (an example of such a steppe climate is to be found in San Diego, California).

Mediterranean Climates Precipitation

During summer, regions of Mediterranean climate are dominated by subtropical high pressure cells, with dry sinking air capping a surface marine layer of varying humidity but making rainfall impossible or unlikely, while during winter the polar jet stream and associated periodic storms reach into the lower latitudes of the Mediterranean zones, bringing rain, with snow at higher elevations. As a result, areas with this climate receive almost all of their yearly rainfall during the winter season, and may go anywhere from 2-5 months during the summer without having any significant precipitation.

As an example, San Francisco in California, USA, receives 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, and receives almost no precipitation at all during the months of July and August.

Mediterranean Climates Temperatures

All regions with Mediterranean climates have relatively mild winters, but summer temperatures are variable depending on the region. For instance, Athens, Greece experiences rather high temperatures in the summer, while San Francisco, California has cool, mild summers due to the upwelling of cold subsurface waters along the coast. Because all regions with a Mediterranean climate are near large bodies of water, temperatures are generally moderate with a comparatively 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). Temperatures during winter only occasionally reach freezing and snow only rarely occurs at sea level. In the summer, the temperatures range from mild to very warm, depending on distance from the open ocean, elevation, and latitude. Even in the warmest locations with a Mediterranean-type climate, however, temperatures usually don't reach the highest readings found in adjacent desert regions.

Inland locations sheltered from or distant from sea breezes can experience severe heat during the summer. Locations inside the Sacramento Valley of northern California, for example, are subject to summer temperatures characteristic of hot deserts (often around 40°C/100°F), although winters are rainy enough to allow lusher vegetation than is typical in deserts. In Perth, Australia hot, dry summers (frequently exceeding 35°C/95°F) and cool, wet winters (with a daily temperature range usually within 10-15°C/50-60°F) are a perfect example of a Mediterranean climate. Unlike the coastal climates that are designated Csb in the Köppen climate classification—characteristic of places with cooler summers—the hotter, typically inland areas have the Csa classification that indicates a hot summer. Areas that experience the typical 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.

Likewise, locations that are slightly higher latitude and cut off from milder ocean winds may have somewhat colder winters and more distinct seasons. This "temperate Mediterranean" climate is most noticeable in northern Italy and northern Greece, as well as southern Oregon. In these areas, plants that are commonly associated with milder Mediterranean climates, such as citrus, date palm, olive, oleander and eucalyptus, can be frozen to death in the occasional severe winter.

Areas of high altitude adjacent to locations with Mediterranean climates may have the cold winters that are characteristic of a continental climate; under Köppen's scheme such places might earn the designation Dsa, Dsb or even Dsc.