Today was a 14 mile run (7 miles out and back). At 7 a.m., it was about 78 or 79 degrees and about 50 percent humidity. Sunrise today was 5:58 a.m. We ran out west, so that means that around 8:10 a.m., we made the turn and were running directly into the sun, 2 hours high in a cloudless sky, with the temp in the low 80s, humidity in the mid 50s percent.
Around mile 8.5, that's when I stopped sweating, and 5 minutes later, the uncontrollable chills started. I had gone through almost 60 ounces of water by that point, so I don't think I was not drinking enough, but, nonetheless, the sun beating directly on my face totally did me in. The chills got worse, and I spent most of the last 5 miles wishing I had a long sleeve shirt or a jacket, which was just dumb. I sat in the shade for about 15 minutes at one point, then just walked all the way back because there was nothing else to do but get back to the start where my car was.
I usually run in the evenings, when the sun is low in the western sky, usually behind buildings and stuff, but out on a trail that runs directly east-west today at 8:30 or 9 a.m., I was at the mercy of the day star. And it won.