On Tuesday, August 5, 2025, people everywhere paused to watch the sky glow with red, orange, and pink as the sun went down. Sunsets are a beautiful end to the day, and many of us wonder what makes the sky change color when the sun sinks low.

Sunlight is made up of all the colors we see in a rainbow. During the day, the sun sits high in the sky and its light travels through less air. Tiny air molecules scatter the shorter blue and violet light in many directions. This scattering makes the sky look blue.

In the evening, the sun sits closer to the horizon and its light must pass through much more air. That extra distance lets almost all the blue and violet light scatter away before it reaches our eyes. What remains are the longer colors, reds, oranges, and yellows, that paint the sky at sunset.

Clouds and weather can change the way a sunset looks! Thin, high clouds catch the red and orange light even after the sun drops below the horizon. They then glow soft pink or gold. Thick, lower clouds can block the sun and make the sky look gray. After a rainstorm, the air is clean and the colors can look very bright and clear. In places with dust or smoke, the reds can look deeper and more vivid.

The angle of the sun also plays a role. Near the equator, sunsets can happen quickly with sharp color shifts. At higher latitudes, the sun moves more slowly along the horizon, creating longer sunsets that blend many shades of red and purple. If you watch a sunset from a mountain top, you may see different layers of color than someone viewing it from a valley or the beach!

Seasonal changes matter too. In winter, the sun’s path is lower and the air is often drier, so winter sunsets can appear more intense. In summer, higher humidity can lead to more scattering and pastel colors. The Earth’s tilt makes each season’s sunsets just a bit different in timing and hue.

People have looked to the sky for weather clues for centuries. The old saying goes, “Red sky at night, shepherd’s delight. Red sky in morning, shepherd’s warning.” A red sky in the evening often means clear weather is coming from the west, while a red sky in the morning can point to storm clouds on the way.

After the sun dips below the horizon, the colors keep changing. First comes civil twilight, when you can still read outside without a light. Then comes nautical twilight, when sailors could once navigate by the horizon at sea. Finally, astronomical twilight fades into true night. During these phases, the sky moves from bright gold to deep purple before turning dark.

Sunsets remind us of the simple beauty in nature’s daily cycles. The next time you watch the sky turn warm shades of red and orange, remember that you are seeing sunlight that has traveled through miles of air. When the short blue light is scattered away, the longer reds and oranges are left to shine!!