We know that solstices are different. It’s colder around the winter solstice and warmer around the summer solstice. We also know that the days are shorter and the Sun is lower in the sky during the winter¹ and that in the summer the days are longer and the Sun is higher in the sky.
[¹In higher latitudes both north and south.]
Afternoon Sun at the Winter Solstice (2019 Reno, Nevada)
People with a high school education probably know that the seasons have to do with the tilt of the Earth’s axis and its orbit around the Sun. And every year, people living north of 30° north latitude or south of 30° south latitude also experience the differences between the summer and winter solstice.
But what does it look like?
Solstices From the Sun’s Perspective
Most of humanity has experienced the solstices from one perspective: standing on the Earth. Astronauts have been able to see Earth from a different perspective, but even they don’t have an immediate comparison of the summer and winter solstices because there is a six-month time lag between them.
Fortunately, we can use a globe and a flashlight to help us visualize the difference between the summer and winter solstice from the Sun’s perspective. Using San Francisco, California, USA as our focal point, we can see how the angle of the Sun’s radiation differs between June and December in the northern hemisphere.
Solstices Sunrise
I’ve used my son’s Kylo Ren figurine standing on the San Francisco Bay area to mark the place on the globe. It should be noted that at this scale, Kylo Ren would be twice the height of the orbit of the International Space Station (ISS).
In Images 1a and 1b, it may not be obvious what is different between the winter and summer solstices; however, in the winter, the Sun is directly over South America as the Sun rises in San Francisco. In the summer, the Sun has yet to reach the South American coast.
What is apparent is that at sunrise in San Francisco, the Sun’s angle is from the east in the summer, and in the winter, the Sun’s angle is from the southeast.
Image 1a – Winter Solstice Sunrise
Image 1b – Summer Solstice Sunrise
[NOTE: A flashlight does not accurately demonstrate the Sun’s light on the Earth. The light of the Sun reaches farther around the curvature of the Earth. Also, the camera is slightly to the right of the light source in these images.]
High Noon
At the point when the Sun is highest in the sky, the difference in solstices is more apparent. In the summer, the Sun is nearly directly overhead but in the winter the Sun is low in the southern sky for North America. [SEE: Images 2a & 2b]
During the winter, people in the United States may find that the Sun is directly in their eyes when facing south. We tend to connect the wearing of sunglasses in the summer, but for people driving in a southerly direction during the winter, the glaring Sun may necessitate sunglasses.
Image 2a – Winter Solstice Noon PST
Image 2b – Summer Solstice 1 pm PDT
Arc In Daylight
The visual that may be best at showing the difference in the solstices is the arc of daylight experienced by a person in winter and summer. The path a person follows in San Francisco during the winter is less than two-thirds the length of the path during summer.
Most of North America crosses the fringe of the solar exposure in the winter while the summer offers a day that is two to three hours longer than on the equator. All this may seem obvious but the differences in the solstices is something that is easier to see modeled than experienced as a passenger on Earth.
Image 3a-b Solstices Arc of Daylight for San Francisco, California
