Yes—fog can help spread warm sunrise/sunset color across more of the sky, but it is not the main reason those colors exist in the first place.

The red/orange color comes mainly from scattering in the atmosphere: when the sun is low, shorter wavelengths (blue/green) are scattered out of the direct sunlight more strongly, so the light reaching you is richer in reds and oranges.

Fog and water droplets are different from the tiny molecules that create the basic red sunset effect. Because fog droplets are much larger, they tend to scatter a broader range of wavelengths more evenly. That’s why fog usually looks white. But when the incoming light is already warm—such as at dawn or dusk—fog can scatter that warm light through a wider area of sky, making the whole scene glow more evenly, somewhat like a diffuser.

In practice:

• strong warm color near the horizon is often due to atmospheric particles/dust
• warm color spread broadly across the sky can be enhanced by water vapor or fog
• if the fog is too dense, it can also mute contrast and reduce saturation

So fog can enhance the look of a sunrise or sunset by spreading the existing warm light, but it doesn’t create the color by itself.