I have a larger dog, around 60lbs who has a thick black coat. He loves to go on walks and hikes. The only problem is that we live in an area that gets hot during the day. When we do go for hikes or walks we go early in the morning before it gets to hot, but he still seems to get a little over heated. Has anyone every put their black dog in a white t-shirt to stay cooler during the summer? Or does this just make the dog warmer bc they have another layer ontop of their coat?