First, you have to know that it reached 72 degrees today. Ten days ago it snowed. Weather is fascinating!
Now back to my "duh" moment. I had a great 5k on October 30th and an even better 10k on November 6th. For both I did something I haven't really done much - stretch before running. I've paid too much attention to the warnings that stretching cold muscles is dangerous. On October 30th it was freezing (no exaggeration) and I had arrived early to the race start and was trying to keep warm. I walked and jogged around a bit and stretched. At the November 6th race, I was also early. It wasn't cold but the plantar fascitis was bothering me and I thought stretching my calves would help.
Tonight I walked out the front door and started running. I felt stiff and clumsy. At about 2 miles I was stopped at a traffic light and decided to stretch. The last 2 miles were awesome. DUH.