Short answer: clouds!
Specifically, mid to high level clouds are needed to create the vivid sunrises or sunsets. Going on day four of sunshine, this morning we were fortunate enough to have a layer of mid to high level clouds stream overhead and as a result, the sky lit up with warm, vivid colors.
When the layer of clouds is just right, the light from the setting or rising sun gets cast onto the bottom of the clouds. Think of them as a canvas for the longer wavelengths of light that we don’t typically get to see (reds, oranges, yellows). If the clouds are too low, these wavelengths are blocked; if there are no clouds at all (like tonight), these wavelengths don’t have anything to project onto.
So the next time you’re looking for that beautiful sunset, be sure to check out how many clouds are in the forecast.
Meteorologist Steve Fundaro