Declination of the Sun Changes Dramatically During August

I'm sure you've noticed that the length of daylight is decreasing across southwestern Connecticut. The mornings are getting lighter later, while the evenings are getting darker earlier. That's to be expected this time of the year. However, have you noticed the subtle change in the length of the shadows? That's due to the lower angle of the Sun in the sky.

It has been nearly eight weeks since the Summer Solstice, and the Autumnal Equinox is just a little more than five short weeks away. The Sun is not nearly as high in the sky today as it was on the first day of Summer. The Sun was 23.26 degrees North of the celestial equator on June 21, which is as high as it ever gets in southwestern Connecticut. The days were at their longest and the shadows were at their shortest.

Today, though, the Sun is just 14.52 degrees North of the celestial equator, meaning that it's nearly four degrees lower in the sky than it was August 1 (+18.10 degrees) and nearly ten degrees lower than it was at the end of June (+23.13). The Sun's lower angle in the sky continues to accelerate through the end of the month. By August 31, for example, it will be just 8.52 degrees North of the celestial equator.

The Sun's rays remain North of the celestial equator through September 23, when the Sun is just 0.10 degrees above it. From that point on, the Sun's rays continue to sink below the celestial equator until December 21, the first day of Winter, when they reach -23.26 degrees. That, understandably, is the shortest day of the year in terms of sunlight.

So, what does this all mean? In short, the Sun's angle is continuing to sink lower in the sky, the shadows outside are getting a little longer each day, and the length of daylight is decreasing each day. The midpoint of Summer was a little less than two weeks ago, and now Autumn is staring right at us. I'm not ready for Summer to leave just yet.

Paul