Climate Regions of Europe
The map below is important to consider when learning about the climate regions of Europe and, in particular, Western Europe. The lines of latitude shown correspond with different cities on both sides of the Atlantic Ocean. Also included is the Equator for reference. The 39 degree north latitude is the latitude our Indianapolis is located. If you follow this line of latitude from Indianapolis to Europe, you will go thru Portugal, Spain, southern Italy, and Greece. If you know anything about those European locales, they have a much different climate than Indianapolis. Think sun, good food/wine, beaches, but a lot of speedos and debt.

In general, those places in southern Europe and along the Mediterranean Sea have more moderated temperatures throughout the year than Indianapolis. This makes sense given that the Mediterranean is a large water body that helps to keep the summer temps from getting too hot, but the winter months don't get too cold. The White River in Indianapolis is mighty, but it has zero impact on the temperatures in Indy as we are far, far away from a coastline. Further, the European places found around the Mediterranean Sea have a much different precipitation pattern compared to Indianapolis with a pronounced summer dry period. More regarding the Mediterranean climate patterns later in this section.

The 51.5 degree north latitude corresponds with the location of London (United Kingdom) and is fairly close to going through Amsterdam (legal drugs) and Berlin (a hole in the wall). Across the Atlantic Ocean from Europe, the 51.5 degrees north line of latitude is actually north of many prominent Canadian cities, including Ontario, Montreal, and Ottawa. Even if you've never been to Canada, most people know that it is extremely cold there, especially during the winter. However, in London, they rarely see snow and temperatures hardly are ever below freezing. The moderating influences of the Atlantic Ocean and the North Sea do help to moderate temperatures in London, but there's more at work influencing the milder climate there.

Finally, the 65 degrees north latitude goes right through Iceland. Just to the west (left) of Iceland is Greenland, which is much colder and less habitable than Iceland. I'm not saying it's not cold in Iceland, but you would expect it to be so miserably cold there that nobody would live there. Further, parts of Iceland are north of the Arctic Circle (66.6 degrees north latitude), which creates a situation in December where they have 24 hours of darkness (no sunlight at all).
EU - Latitude Map.jpg
(base map source: Wikipedia)

So what's causing these seemingly wonky climate patterns for places on opposite sides of the Atlantic Ocean, yet at the same line of latitude (distance from the Equator)? How do the British not have brutally cold winters and rarely see huge snowfalls or blizzards in North America? Why is Iceland actually somewhat livable even though it is so far north and close to the North Pole?

The answer to these two questions relates to the North Atlantic Current and the Jet Stream. Without this specific pattern of ocean surface currents, hardly anybody would want to live in Northern Europe or the British Isles. The map below is from the NOAA (National Oceanic Atmospheric Administration) and shows the locations and principal flow directions of the Earth's major ocean surface currents. Off the coast of eastern North America is the "Gulf Stream", which originates from the Caribbean region, works its way north along the United States coastline, before moving eastward across the Atlantic Ocean towards Europe.

The map below focuses just on the Gulf Stream by further showing the movement of the North Atlantic Current. Note the red (warm) and blue (cool) tones of the arrows correspond to ocean surface current temperature. Technically, the North Atlantic Current, which acts like a conveyor belt, brings warm, tropical waters from as far as Africa across to the Caribbean Sea and Middle America. Here, the current moves from the Gulf of Mexico (thus the name "Gulf Stream") towards the United States' eastern coastline. Keep in mind, this is still some rather warm water/currents that then move towards Western Europe bringing much warmer temperatures than we would otherwise expect for this far north of a latitude/location.

Possible Exam 4 Question: Describe the Mediterranean climate region and make some connections between the climate and food/drink of this area.

Below is a map of the climate region types found in Europe. In the following video, this map is used to further generalize about climate (and booze) patterns.

(map source: Wikipedia)