This is because the shorter the wavelengths of light, the better it scatters off of air and water particles. Blue Light So blue light, which has very short wavelengths, is much more likely to scatter than the longer wavelengths, like red light. This means that when blue light hits the water particles, it’s more likely bounce off, going back into your eyes, and reducing your ability to see through the fog. It also increases the glare for everyone, since blue light scatters better inside our eyes as well. In the regular headlights, there are still a fair amount of smaller wavelengths, so it scatters too. But since it also has more of the longer wavelengths, more light gets through the fog. So you can still see–sort of.