Final answer:
The climate of Western Europe is significantly warmer and milder because of the Gulf Stream.
Step-by-step explanation:
The effect of the Gulf Stream is that the climate of Western Europe is significantly warmer and milder than it otherwise would be.
The Gulf Stream is a warm ocean current that originates in the Gulf of Mexico and crosses the Atlantic Ocean to Europe. It pulls warm water from the tropics and circulates it north, off the coast of Europe, which moderates the temperature of Western Europe.
This is why most of Western Europe has a moderate type C climate, even though it is located at a northern latitude.