Why Marine West Coast Climates Are Narrow in N. America but Wide in Europe

The contrast stems from three geographic factors:

1. Continent Shape & Orientation: North America's compact, meridional (N-S) shape lets cold, dry continental air reach the Pacific coast easily, pinching the marine zone. Europe's zonal (E-W) extent, peninsulas, and inland seas allow maritime air to penetrate deeply.
2. Ocean Currents: The cold California Current (North Pacific) cools and stabilizes onshore air, limiting evaporation and precipitation. The warm North Atlantic Drift (Gulf Stream extension) brings mild, moist air to Europe's west coast.
3. Mountain Barriers: N. America's coastal ranges (Rockies, Cascades, Sierra Nevada) are high, continuous, and perpendicular to westerlies—blocking maritime air (rain shadow). Europe's mountains (Scandes, Alps, Pyrenees) are lower, fragmented, or parallel to flow, allowing maritime influence inland.

Result: N. America's marine west coast climate is a narrow coastal strip (SE Alaska to N. California). Europe's spans Norway to N. Spain and reaches deep into Germany, Poland, Russia.