My wakeup HR was 51 this morning. Our low last night was 15 (F), but when I left home for my hour run in mid afternoon, the shade temperature was 33 (F). When I returned home, the sun had just dipped behind the mountains, and the temperature was 31 (F).
I started my run with three layers, but I removed my wind breaker after a mile and a half, and I felt comfortable during the run. However, as the sun was starting to dip behind the mountains, I could feel that the temperature was dropping.