|WHAT PRODUCES THE COLORS IN THE SKY?
METEOROLOGIST JEFF HABY
The lack of sunlight produces darkness and the color black. At night, the sky will be black. The color
that is in the sky at night is due to city lights and other manmade lights that can light up
clouds and the horizon.
During cloudy skies the color of the sky will be a white color or a shade of gray. The thicker the
clouds the grayer it will be. Light is made up on the colors of the rainbow. When the colors
are put together it produces white. This is why clouds are often white.
When the skies are partly cloudy you will see both the colors white and blue in the sky. The white
is from the reflection of the visible light off the clouds. The sky is blue because it is the blue light
that is reflected or scattered best by the air. This scattering produces blue light coming from all directions, thus
the sky will appear blue.
You have probably seen a rainbow. In that case all the colors are shown like light going through
a prism. The colors are ROYGBIV (Red, Orange, Yellow, Green, Blue, Indigo, Violet). Raindrops in
the air act like prism. Raindrops are much bigger than cloud drops and the raindrops are often
making it all the way to the ground while the clouds are higher up. The huge number of raindrops
each act like a prism and when all put together produce the rainbow. The sun needs to be near the
horizon and rain falling on the opposite side of the sky from where the sun is in order to
see a rainbow. It is these conditions that produce the rainbow effect.
At times the sky will appear red and orange. This can occur when there is dust in the sky. In can also occur
when the sun is close to the horizon. When the sun is close to the horizon the sunlight must
travel through a greater distance of the atmosphere and this gives enough time for the red
light to scatter out. Dust can make the sky appear red since the color of the dust itself is a
reddish color and red light is scattered off the dust especially as the sun gets closer to the
horizon. Sunlight near the horizon will also make nearby clouds a shade of red, orange and violet.
At other times these colors below can be seen:
Green: A storm with hail and very heavy rain can scatter greens, red and purples to make the
storm look very threatening
White: The sky can be white even with no clouds during the day at times there is smog or smoke
in the air
Shades of gray: In partly cloudy conditions or with developing thunderstorms, different portions
of the clouds will be different shades of white, gray or black. Where the sun is directly shining
on a cloud will be bright white. The shadowed portions of clouds will appear as shades of gray. Very
thick clouds can appear black on the shaded side.
Each time you are outside, look at the colors in the sky and think about what is causing the