Why is the Mediterranean region warm?

I was looking at a globe and I noticed the cities like Rome and Athens and Marseilles are about as far north as cities like Chicago and Buffalo and Toronto. But they clearly do not have the same overall climate.

I understand how the gulf stream current brings warm water up and keeps places like Spain, Britain, and Scandinavia warm. But I assume relatively little warm currents make it through the strait into the Mediterranean.

Is there some obvious reason why balmy breezes blow off the Mediterranean and not the Great Lakes?

If I’m not mistaken, the American east coast suffers from both cold sea currents coming from the north and cold winds coming from the west.

This might explain the difference.

And the US has two long N-S strings of mountains, but very little going on horizontally. The area around the Med has much more rugged terrain with many mountain chains going E-W; dominant winds over most of Spain are westerlies (on the North) or easterlies (on the South and on most of the Eastern coast). There is also a real big dry, hot desert right over there points south over the Atlas Mountains, which is also further North than similar-looking places in the US.

In the Northern Hemisphere, the air currents over the oceans moves counter clockwise. As such, the West coast of a continent in the Northern Hemisphere is significantly warmer than a location at the same latitude on the East coast.

For example, Sapporo (5m annual snowfall) is at about the same latitude as Barcelona (0 snowfall), which is also at the same as Eastport, Maine (1.7m), and North Bend, Oregon (0).

Don’t forget that the water in the Mediterranean gets heated up in summer and retains much of the heat into autumn and winter.

Yeah, but why don’t the Great Lakes, is his question.

The main reason west coasts of Europe/North America are milder in winters is due to the maritime air mass. The mean flow between 35N and 50N is generally westerly, meaning they are largely influenced by the water to the west. Conversely, central/east coasts of continents (Asia/North America) are influenced by continental air masses, so it is colder in the winter, and hotter in the summer (land gains/loses heat faster than water).

As far as the Mediterranean is concerned, the main reason is due to the Alps, which prevent cold air masses from penetrating so far south. This, combined with the fact that there is no true arctic/polar cold air source region over northern Europe (due to the Gulf Stream waters west/north of Scandinavia), means cold air outbreaks are rarer than in North America/eastern Asia. The cold air would have to originate over Russia and move west/southwestward. Since again, the mean flow is from the west, this doesn’t happen very often. So, cold snaps are occasionally experienced over northern/northwestern Europe, but very rare (I’m not sure how rare) south of the Alps. So, this explains the warmer air generally in the winter. In the summer, the area is fairly similar to other similar latitudes, which also heat up pretty rapidly.

It’s the source of “gota fría” (“cold drop”) rainstorms, the heavy rains which take place every fall: on the shores of the Mediterranean itself, most of the year’s rainfall comes down in a few weeks around September-October. It also happens unseasonally, but it’s more rare. This year has been colder than usual due to Siberia wanting to share (no thanks, you can keep that cold air, serious, we mean it).

I don’t see how the ocean can have a major effect on places like Rome - Rome is farther from the Atlantic than Chicago is and nobody would call Chicago an oceanside city.

But the point about the Alps (and the Carpathians and Pyrenees) is good. I can see how they would block the colder weather from traveling south into the Mediterranean region. Presumedly if Ontario had a similar mountain range, the midwest would have a more temperate climate.

And remember that it isn’t only the Alps, a lot of central Europe would be considered “big mountains” if you dropped those “hills” someplace in Illinois. Greece, Italy and Spain are more likely to get cold weather from Siberia via Kiev than to get it coming from Northern Europe. Dominant winds in the US may still be westerlies, but there were times when I was in Florida when a cold weather front would reach us all the way over there, courtesy of Canada, and the wind arrows on the weather map were all pointing N-to-S.

The so-called “Mediterranean Climate” occurs in only a few places besides the Med itself - California, Chile, Southwestern Australia, South Africa:


That second article has this to say about controlling factors:

(CA’s “Mediterranean Climate” is why it’s prey to Mediterranean invasive species, such as the yellow starthistle covering huge portions of the state - the stuff belongs in Greece and Italy.)