I looked at the temp picture at lunch time today, and it was 83, just below my cutoff. I decided to go for a hot run, especially since the evening temp was slated to stay above 85 till after 8 PM. While changing I discovered that I had failed to pack socks. The choices were 1) dress socks, 2) no socks, 3) no run. I went with the fashion-conscious choice, #2. No big deal I thought, I had run sockless before, and besides sweaty feet, it was no problem. That was in a different pair of shoes, I guess. I had to stop at mile 1.15, with my right Achilles tendon rubbed raw. By the time I walked back to the office, it was bloody, and the left one was raw as well. Fortunately I was able to salvage 5 more miles this evening, but not until after 9 PM. And it's still 83.