When we look at a sunset, the colors we see in the sky are often a mix of orange, pink, red, yellow, and purple hues. But which color dominates – orange or pink? The answer depends on a few different factors.
Most sunsets tend to appear more orange overall, but can have pink hues mixed in. The orange comes from the sunset reflecting off dust and particles in the atmosphere. Pink, red, and purple hues are caused by light scattering. Sunsets with more pink are often seen after events like volcanic eruptions or wildfires put more particles in the air.
Why are sunsets orange?
The primary reason sunsets usually look orange is due to the way sunlight interacts with the atmosphere. During the day when the sun is high in the sky, its short wavelength blue light scatters more easily, which makes the sky look blue. But around sunset, sunlight has to pass through more atmosphere and air pollution to reach our eyes. This atmospheric scattering filters out more of the short blue wavelengths, allowing more of the long orange/red wavelengths through. The orange sunlight is also bounced off dust particles and water droplets in the atmosphere, adding to the orange tones.
Why are some sunsets more pink?
While orange hues tend to dominate most sunsets, some can take on more pink, purple, and red tones. These types of sunsets happen when there are more particles in the atmosphere for the setting sunlight to interact with. Events like volcanic eruptions, wildfires, and dust storms can increase the amount of particulates and aerosols high up in the atmosphere. These extra particles make the sunset light scatter more strongly, filtering out yellows and oranges and allowing more pink, purple, and red wavelengths to come through. The pink hues are created when the long red light waves scatter and blend with the short blue waves in the upper atmosphere.
Other factors that influence sunset colors
A few other things can affect the balance of orange and pink hues we see in the evening sky:
- Pollution – More pollution particles like smoke, haze, and smog can create more vivid red and orange sunsets.
- Cloud cover – Clear skies allow us to see more direct sunlight, while clouds diffuse the light, often making sunsets more pink.
- Angle of sunlight – Lower sun angles at higher latitudes mean sunlight passing through more atmosphere, often resulting in more orange-pink hues.
- Time of year – Sunsets shift from more pink in winter to more orange in summer as the sun’s angle changes.
Typical distribution of sunset colors
While individual sunsets can vary a lot, we can analyze hundreds of sunset photos to see the typical distribution of colors on average:
This data shows that on average, orange makes up over half of a typical sunset’s color scheme. Pink is the next most common at 25%, followed by smaller amounts of red, yellow, and purple hues.
Famous pink sunsets throughout history
While orange prevails in most normal sunsets, there have been periods throughout history when pink, red, and purple sunset skies persisted for months or even years at a time due to particles emitted from volcanic eruptions or wildfires:
- 1883 – Krakatoa eruption – The massive eruption of the Krakatoa volcano in Indonesia in 1883 caused vibrant red and purple sunsets worldwide for 3+ years afterwards.
- 1991 – Pinatubo eruption – The eruption of Mount Pinatubo in the Philippines in 1991 led to unusually colorful sunsets for about 2 years.
- 2020 Western wildfires – Intense wildfires in the western US in 2020 created blood red and deep orange sunsets that persisted for weeks.
- 2023 Australian wildfires – Severe bushfires in eastern Australia are currently producing dramatic vivid pink and red sunset skies.
These events injected massive amounts of ash, soot, and particulates high into the atmosphere, causing the unusual and prolonged pink and red sunsets as the particles scattered sunlight at sunset.
Beauty in both orange and pink sunsets
Whether a sunset leans more towards vivid orange or delicate pink, the colorful evening skies never cease to amaze. The beauty in both types of sunsets comes from the incredible interactions between sunlight and our atmosphere. Orange sunsets showcase the scattering effects of pollution and particles at low altitudes close to the horizon. Pink and red hues reveal high altitude scattering where sunlight interacts with air molecules, volcanic emissions, and wildfire smoke. Sunsets give us a stunning visual look at the complex physics and chemistry of our atmosphere.
While pink can play a striking role, the typical sunset usually appears more orange overall. But the balance of colors varies a lot between locations and conditions. The scattering of long red and short blue wavelengths through differing amounts of particles produces the palette of orange, pink, purple, and red hues seen in the transitional sunset sky. Whether natural or human-caused, the particulates and aerosols that sunsets reflect off of provide breathtaking evening color across the world.