What exactly is a mediterranean climate anyway?

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At first glance that's a stupid question. We all know what a mediterranean climate is -- it's dry warm summers and cool wet winters. That's like asking what a mountain is; we all know one when we see one.

 

Or do we? In the eastern United States, the Appalachians are considered a mountain range. In northern India they'd be foothills. I think we have a similar problem with mediterranean climates. For example, the specific weather that people call "mediterranean" in much of Europe is quite a bit different from the specifics California. In fact, the more closely you look at them the more different they start to look.

 

Speaking as a Californian who successfully grows some mediterranean plants and fails consistently with others, I'm convinced that many of my struggles have come from a naive assumption that everything "mediterranean" needs the same basic conditions.

 

We've had a lot of discussion of this topic over at the Pacific Bulb Society, and a couple of us ended up creating charts and maps comparing the various mediterranean climates around the world.  The results were interesting to me, and I wanted to share them here.  A few highlights...

 

--South Africa and Western/Southern Australia have the mildest climates. Compared to the other mediterranean regions, they are a bit milder in winter and have less severe droughts in summer.

 

--California's mediterranean climate may be the hardest on plants. It generally has colder winters and drier summers than the other regions.

 

--Coastal Oregon and Washington have weather that resembles a mediterranean pattern in many ways. Officially, climatologists do not classify them as mediterranean, but for plant-growing purposes I think of them as semi-mediterranean. The same thing applies to south-central Chile.

 

--Central Chile's pattern is similar to California's, although a bit milder in many areas.

 

--Europe is a mix of all the other regions. Spain, southern France, Italy, and Morocco/Algeria all have comparatively moist summers. The Greek islands and the Middle East have very dry summers.

 

If you're interested in checking out the maps, you can see them here: http://www.pacificbulbsociety.org/pbswiki/index.php/MediterraneanMaps  Your comments and suggestions are very welcome.

 

I should also note that Sean O'Hara has put up some interesting comparative climate information on the gimcw website here: http://www.gimcw.org/climate/

 

Mike

San Jose, CA (zone 9, min temp 20F / -7C)