Are Golden Retrievers double-coated?

Yes, Golden Retrievers are double-coated. Their long, smooth outer coat is oily and waterproof and protects them from the elements, dirt, and other debris. Their undercoat is thick, soft, and fluffy and helps protect them from excessive heat and cold temperatures. 

When the weather gets warmer, Golden Retrievers shed their winter undercoats to make way for a lighter summer coat. Then, when cold weather starts to creep in, they shed their lighter undercoats and grow thicker, warmer coats for winter.