Why is rising sun red

In the mid-latitudes, the prevailing winds are westerlies. This means storm systems generally move in from the west. The colors we see in the sky are due to the rays of sunlight being split into colors of the spectrum as they pass through the atmosphere and ricochet off the water vapor and particles in the atmosphere.

The amounts of water vapor and dust particles in the atmosphere are good indicators of weather conditions. They also determine which colors we will see in the sky. During sunrise and sunset the sun is low in the sky, and it transmits light through the thickest part of the atmosphere. A red sky suggests an atmosphere loaded with dust and moisture particles. We see the red, because red wavelengths the longest in the color spectrum are breaking through the atmosphere.

The shorter wavelengths, such as blue, are scattered and broken up. According to the National Weather Service, when we see a red sky at night, this means that the setting sun is sending its light through a high concentration of dust particles. This usually indicates high pressure and stable air coming in from the west. Basically good weather will follow. A red sunrise can mean that a high pressure system good weather has already passed, thus indicating that a storm system low pressure may be moving to the east.

A morning sky that is a deep, fiery red can indicate that there is high water content in the atmosphere. So, rain could be on its way. This means most of the yellow, orange, and red light passes through while a small amount of blue and purple light is scattered and removed from the mix. The Sun, therefore, looks yellow for us here on Earth. Due to Rayleigh scattering, most of the light of shorter wavelengths — the blue, violet, and green — are scattered away multiple times, leaving only lights of longer wavelength — the red, orange, and yellow — to pass straight through to the observer.

This is why a rising and setting Sun tends to take on spectacular hues of red, orange, and yellow. The quality of the air that sunlight has to pass through also has an effect on the color of sunrises and sunsets. Dust particles and pollutants tend to tone down the colors in the sky as well as impede light from reaching the observer on the ground. Because of this, the sky takes on dull hues of red and yellow when the air is full of dust and pollutants.

This is why sunrises and sunsets in rural areas, over the ocean, and deserts are much more vibrant and colorful than over cities and urban areas. Tips: Take pictures of sunrises and sunsets. Rayleigh scattering is also responsible for giving the Moon a reddish or orange hue during lunar eclipses. The condition of the Earth's atmosphere, including the amount of pollution and dust from storms and volcanic eruptions, can affect the shade of red the Moon takes on during the eclipse.

Topics: Astronomy , Sun , Atmospheric Phenomena. Sign in.