Skies in Western Australia were glowing red recently, giving it an eerie, apocalyptic aura.

Multiple factors played a role in this, most of which are rooted in science.

Atmosphere

When sunlight hits the atmosphere, it appears white most of the time. But it’s actually all the colors of the rainbow scattered and interacting with gas molecules, dust, and microscopic water droplets.

When the sun is directly overhead, the sky looks blue because shorter wavelengths of light are easily scattered. When the sun angle is low, as at dawn or dusk, light has to pass through more of the atmosphere and appears red and orange due to its longer wavelengths.

Microscopic Air Particles

Skies can also appear vividly redder whenever there are more microscopic air particles in the sky than usual. This can be anything from dust to wildfire smoke to pollution.

In Western Australia, winds from Cyclone Narelle off the coast likely kicked up much of the desert sand, leading to a redder sky.

These larger particles enhance something called Mie scattering, which boosts the red and orange tones and can make the sky look dramatically deeper in color—sometimes even blood-red.

“Red Skies at Morning”

The common phrase “red skies at morning, a sailor’s warning” might actually have some truth to it.

A red sky in the morning can indicate that the sun is shining on clouds coming in from the west, a sign that rain could not be too far behind.

As with dust and pollution, when the sun shines on these microscopic water particles at a low angle in the morning, they will glow red and orange.

Bottom Line

Skies in Western Australia were likely influenced by all of these factors. It stands as a reminder that while uncommon, red skies are signs of physics at work around our large and complex planet.