What is a Mediterranean climate?

Michael Mace mikemace@att.net
Wed, 03 Feb 2010 23:31:00 PST
We all know what a Mediterranean climate is -- it's dry warm summers and
cool wet winters.  But when you look more closely, the details vary from
region to region.  For example, the specific weather that people call
"Mediterranean climate" is quite a bit different from the specifics in

I'm convinced that many of our struggles to grow bulbs and other plants from
Mediterranean climates come from an assumption that everything
"Mediterranean" needs the same basic conditions.

Lee Poulsen created some fantastic charts a few years ago comparing rainfall
in various "Mediterranean" cities.  When he graphed the rainfall in those
cities, he found important differences -- some "Mediterranean" cities still
get significant amounts of rainfall in the summer, and the length of the
summer "dry" period varies tremendously.

Lee's work inspired me to see if I could create climate maps of the
Mediterranean regions, all formatted the same way, so we could easily
compare climates from one region to another.  After a lot of work, I've
finished a draft of the maps and posted them to the wiki, with a detailed
(maybe too detailed) explanation.

I haven't linked to the page from the rest of the wiki yet, because I'd like
to gather comments first.  So the only way to get to the page is to use this
web address:


Some tidbits from the maps

--South Africa and Western/Southern Australia have the mildest climates.

--California probably has the harshest Mediterranean climate.  It has colder
winters and drier summers than the other regions.

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

--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.

--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.

What it all means

Here's what I think the maps are telling me about growing Mediterranean
bulbs and plants in California:

--Why do so many of my South African Amaryllid bulbs need supplemental water
in the summer?  Because they are used to getting some summer rainfall.

--Why do many European bulbs naturalize well in gardens that get year-round
water, when that kills bulbs from places like California?  Because many
areas in Mediterranean Europe get more summer rain than any other
Mediterranean region. 

--Why do I have so much trouble growing Australian plants?  Because they are
used to warmer winters and milder summers than I have in my part of
California.  Even if I protect them from frost, planting them out in the
garden with no supplemental water in summer is likely to put them under
enormous stress.  No wonder they grow better along the mild, damp coast of

Questions for you:

	What do you think of the maps?
	Are there errors I need to fix?  Things to add?
	Is this useful?
	Do you think this is appropriate to post on the PBS wiki?

Thanks in advance for your feedback.

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