I was late getting out (11 am). The temperature was in the low 80s (F) in the shade and probably 110 or higher in the sun. It was hot. I did pretty good during the first mile and a half, but the heat got to me during the last mile (especially the last half mile). I drank my 16 oz. of water and went slower. During the last mile, I stopped at benches that were in the shade and sat down.
My wakeup heartrate was 61, significantly higher than last Saturday. I could tell I was tired, and I didn't expect to have a great run.