Not all 50 degrees (F) are the same

The temperature when I left for my run was about 52 (F), and it was 44 (F) when I returned. The sky was cloudy, and it looked like it was storming over Long Peak (elevation about 10,000 feet). I wore my nylon wind breaker during the run, because there was a cold wind (5 mph) blowing. If I ran in the summer when the temperature was 50 (F), I would enjoy the coolness and the relief from the hot summer sun. However, this morning the 50 degrees was cold and I was glad for my second layer to break the wind.