DENVER (KDVR) — When the sun sets, sometimes there are pink and purple colors across the skyline, while other times, the sky stays blue before it fades into nighttime.

The sunset won’t always be perfect, but it turns out, there’s a way to know if the sunset will be good before it happens.

According to meteorologist Travis Michels at Nexstar’s KDVR, it’s not necessarily a forecast meteorologists look at when broadcasting weather, but there is a science behind it.

Nice sunsets usually occur when there are partly to mainly sunny skies. This is not only because you can see a clear sunset, but for colors to show, the sky needs to have some clouds, according to Michels.

Clouds help show the colors because as the sun rises or sets, light passes through more of the atmosphere and hits more particles, according to Michels. Those particles can be natural or manmade dust and pollutants.

When the light hits the particles, it scatters, bounces and changes direction, which slows the wavelength of the light, in turn changing the color.

“Think of it with the prism of color, ROYGBIV, the wavelengths change from slow to fast, and depending on how much scattering there is, that’s how the light is different colors,” said Michels. “More scattering (slows the wavelength) is more orange and red, while less scattering (keeps the wavelength faster) leads to more blues and whites. That’s why the sky is blue during the day.”

When wildfire smoke fills the sky, like it did for much of the country last summer, sunsets can also become a distinct color.

That smoke, like clouds, acts like a filter that only lets longer wavelengths through, meteorologist Paul Wetzl of Nexstar’s WKBN explains. This not only causes a red and orange sunset but a glowing red sun during the day.