Warm colors and cool colors are discussed in art. They also apply to photography. Blue, green, and purple would be your cool colors, while red, orange, and yellow would be your warm colors. Each group sets a mood that is opposite of the other.
Cool lighting is used to establish a calm or gentle mood. The blues and the purples also make the picture more relaxing and easier to look at than the warm-colors. Good examples of cool color pictures would be the Aurora Borealis and of marine wildlife.
On the other hand, warm colors are very intense. They contrast from cool colors as they are not easy to look at, and usually are very bright. Explosions would be the best example of warm colors.