BOSTON (CBS) – In case you haven’t noticed, the sunrises and sunsets this month have been AMAZING! Almost every day we are inundated with images from the audience, each one more impressive than the other.
So, what’s up?
First of all, the weather that November was very pleasant. I don’t know about you, but when I think of November I think of bare trees, cloudy skies, and generally cloudy weather. This month the opposite was true. Boston hasn’t had a drop of rain this month and almost every day there was a clear sky with only a few tall, thin cirrus clouds.
But as it turns out, there’s a lot more to it than that! The time of year plays a big role in the number and vibrancy of sunrises and sunsets. Believe it or not, late fall / winter is the absolute best time of the year for sunrises and sunsets.
There are several reasons for this, but let’s start with the basics first.
Why do we get beautiful colors at sunrise and sunset?
The color of the sky that we see every day is caused by something called Rayleigh scattering. The light of the sun contains all the colors of the rainbow, but each has different wavelengths and therefore reaches the earth in different concentrations. Our skies are blue most of the time, thanks to the abundance of nitrogen and oxygen in our atmosphere, which tend to scatter the shorter wavelengths of blue and purple more effectively. At sunrise and sunset, sunlight needs to cross more atmosphere to reach our eyes, so the blues, yellows and greens are already scattered and the reds and oranges are left behind.
Why is this effect even more dramatic at this time of year?
The dust and air pollution (usually more so in summer) can reduce the intensity of the sky color. This is due to the added particles in the atmosphere that can scatter sunlight. The summer haze tends to muffle the sky color, while the clear and clean air in the fall allows more reds and oranges to pass through.
The more moisture (water vapor) there is in the air, the duller the colors. New England is known for the classically cool and dry nights in late autumn and winter. Lower humidity = more vivid colors.
Obviously we have a lower position of the sun in our northern latitudes in autumn and winter. As already mentioned, the lower the angle of the sun, the more atmosphere the light can pass through and again the longer wavelengths (red and orange tones) remain.
Perhaps the biggest and most important factor in any season of the year for a vivid sunset is the clouds. Obviously, if you have low cloudiness you will not get a sunset. The ideal conditions for the perfect sunset are high, thin cirrus clouds, mostly made up of ice crystals. These are often associated with an incoming storm system, but can also be present in fair weather.
There you have it! Everything you always wanted to know about sunsets but dared not ask.
BTW, if you have great sunrises or sunsets, send them along! We’d love to see you! Email to email@example.com.
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