As the seasons change, so do the temperatures and type of weather we will see.
But did you know the color of the sky will change too?

The seasonal differences with blues in the sky all come down to the composition of the atmosphere combined with where the sun is in the sky.

In the spring and summer, we get these beautiful light blues. Sometimes it’s kind of a milky appearance… and some days it’s such a light blue that it almost looks white. But in the fall and winter, that’s when we get the richer blues. They’re especially pronounced with a snowy landscape… which many of us have seen here in North Dakota.

Maybe you haven’t noticed a difference in the sky colors… maybe you have and you didn’t know why but the transition can be so subtle over several months that it can be hard to notice.

The summer sky has more water vapor. The warmer the air the more water it can hold so the larger the water droplets. Those larger water droplets scatter light into a milky white haze The higher the sun angles, the more scattering. Our eyes perceive this as a lighter blue and sometimes almost white.

In the winter we have much drier air. It’s colder so it doesn’t have the ability to hold much moisture. So the water droplets are much smaller. Combined with lower sun angles and we have a limited amount of light scattering which favors more deep blues and purples. This is why our eyes perceive a richer blue.

This same principle applies to sunrises and sunsets with golden hues … the sunlight is scattering in the atmosphere. The longer the scattering, the more oranges and reds your eyes pick up.