Oceanic or Mediterranean? (updated)

 

One of the characteristic climates (8 or more months above 10ºC) of west coasts is the subtropical oceanic Cr¹, whose rainfall pattern reflects the frequency of extratropical cyclons and its westerlies, which is higher in winter than in summer, when the subtropical highs move poleward following the apparent course of the Sun.

Its temperate counterpart is the D_or climate, a subtype of the temperate oceanic D_o (e.g. Brest) of the original Trewartha classification, which for the most part covers the Köppen Cfb climate. The criterion for the r subtype¹ is that at least 65% of the yearly precipitations must be concentrated on the winter half-year (October-March on the northern hemisphere and April-September on the southern hemisphere) and the rainfall of the driest month must be 30 mm or more.

When 1-2 summer months have less than 30 mm of rainfall we've got a Crs climate (e.g. Rome), transitional between the oceanic and the Mediterranean Cs. Its temperate counterpart is the D_ors (e.g. Portland).

These climates where classified as Mediterranean under Köppen, despite the fact they're more rainy (and in the case of D_ors also cooler) than actual Mediterranean climates, as for example San Francisco, whose summers (16.7 ºC in September) are cooler than Portland's because of its coastal location along a cold ocean current, which causes a persistent fog like in the coastal desert climate (Trewartha BM or Köppen BWn) found southward.

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¹ Which stands for rainy and was originally introduced by Trewartha for the tropical rainforest climate Ar (Köppen Af).
² For which Köppen introduced the n subtype, from German Nebel 'fog'.