If you happened to be out and about this past weekend you might have gotten a little extra sun, especially if you didn’t have the sunscreen on!
Believe it or not but the amount of sunshine or the intensity of sunshine is the exact same as it is in late August! We can calculate this using what’s called the azimuth, or the angle an object is above the horizon. Just like when we see the forecasts for the ISS flying over, which are given in degrees above the horizon, we can use the same coordinate system for the sun!
So because the Earth moves around the Sun, and the tilt of the Earth is at 23.5º the highest point the Sun is in our sky changes every single day!
With the astronomical viewpoint laid out here’s how this looks on Earth, specifically in the Quad Cities.
So at the Winter Solstice, we experience the shortest day of the year and the Sun at its lowest azimuth of the year at just 25.1º above the horizon here in the Quad Cities!
Inversely, the Summer Solstice has the longest day of the year, and the sun is at its highest azimuth at 71.9º in the Quad Cities.
During the Equinoxes the azimuth of the sun is right in the middle at 48.5º, which if you subtract 48.5 from 90º that comes out to 41.5º, which is our latitude North here in the Quad Cities!
With that in mind, today’s solar azimuth is at 62.5º above the horizon.
62.5º is the Solar Noon Azimuth on April 27th, as well as August 15th! So, if you were outside this past weekend and noticed the extra sun intensity that’s because it’s exactly the same as it is in late Summer!
As the weather keeps getting nicer outdoors it’s a good idea to remember to be applying sunscreen, especially for this time of the year as temperatures aren’t as hot as it is in August. Either way the UV index values are about the same this time of the year as it is in late Summer.