The arrival of summer in the northern hemisphere is welcome, for many reasons. There is a minor downside, if one plans to make a sunrise trek to the peak of Prairie Mountain in Kananaskis: the early start. Of course, my friend Tim hatched the idea, as the perfect complement to our winter solstice hike last December. If you haven’t read my blog pieces for that epic outing, here are links to Part One (the hike) and Part Two (the science).
My first reaction was “I’m in!” Then, when the reality of the required 2:50 a.m. departure from Calgary set in, I found several excuses to bail out. To Tim’s credit, he persevered and he managed to wrangle a couple of friends to join him. He didn’t even mind sharing his photos, so I could pretend to have been there!
The Hike
Tim, Jerry and Peter departed the Prairie Mountain trailhead at 3:50 a.m. and reached the summit in time for the 5:21 a.m. sunrise. Tim commented that it was amazing to see the full moon go down in the west while the sun was coming up in the east. He mentioned that while he knew the sun would break the horizon much further north than it did on the winter solstice, it was even more of a difference than he expected. More on that later.
Here are a few photos from their hike:



The Science (abbreviated)
For the winter solstice, you may recall I did some research on the unexpected timing of the solstice, and why the day with the latest sunrise wasn’t the same as what we think of as the shortest day of the year. If you are interested in orbital eccentricity, angles of obliquity, and other astronomical wonders, you can read about them here.
Since it’s summer, and I’m feeling a bit lazy, I did a shortened version of the research. You’ll be happy to know that I confirmed the same factors affect the timing of the summer solstice. Here’s what I found:
- the summer solstice occurred at 2:50 p.m. on June 20
- the day with the earliest sunrise was June 16 (5:20 a.m.)
- the longest solar day was June 20 (16 hours, 33 minutes, 17 seconds)
Tim’s comment about the sun’s compass direction at sunrise on June 20 compared to the direction on December 29 got me thinking. I marked up a trail map for the area of Prairie Mountain. The arrows show the sun’s compass direction at sunrise and sunset, on the summer (blue) and winter (red) solstices, respectively. What’s interesting is just how much the sun’s coverage changes between the two solstices.

The apparent travel of the sun (because it’s the earth that’s moving around the sun, after all) is from 128 degrees at sunrise to 233 degrees at sunset on the winter solstice. That’s a span of 105 degrees. In contrast, the sun traverses a range from 49 to 311 degrees at the summer solstice… a span of 262 degrees.
Isn’t that fascinating? I think so too.























