Week of August 28, 2022 – September 3, 2022
by Elizabeth Suzedell, Environmental Educator
As a lover of all things weather, especially clouds, sunset is my favorite time of the day. There is quite the contrast between the light blue skies with white or gray clouds at noontime and the bright warm colors you can see at the end of the day. Sometimes, sunsets look as if someone took a paintbrush to the sky with vibrant hues of pink, orange, and yellow. Other times, the sky may just slowly darken to a dark navy without much of a show.
Scattering of light is the phenomenon that causes the sky to turn to red during sunset. This is also what causes the sky to appear blue during the day. The sun emits some of its light in the visible spectrum, which is the light that our eyes can see- all of the colors of the rainbow (red, orange, yellow, green, blue, and violet). When the colors are combined, they show as white light from the sun.
Warmer colors have longer wavelengths (red end) while cooler colors have shorter wavelengths (violet end). When this light passes through the gas molecules in the atmosphere during the day, the blue and violet waves are the right size to be separated from the rest of the light. The gas in the atmosphere then “scatters” this light across the sky, making it appear blue (it scatters violet light as well, but our eyes are more sensitive to blue light).
During sunset (as well as sunrise), the sun is much lower in the sky compared to earlier when the sun was more directly overhead. Because of this, the light must travel through more atmosphere before it reaches you. The sky turns to the warmer reds and oranges because there are more molecules to scatter the light.
Clouds and atmospheric conditions play a big role in the outcome of each sunset. Having middle and high level clouds, which are high enough to reflect the sun’s rays, create the most breathtaking sunsets. It is important to have enough of them covering the sky, but not so much that there is no space for the sun to shine through near the horizon. The colder air that will come soon as we head into fall and winter is much drier and it tends to be cleaner than summer air. While impressive sunsets can occur all year, these conditions are most ideal. If you will miss the long and warm summer days like I will, at least we are more likely to experience more amazing sunsets!