Notes
At the Silver Comet doing an 18 mile long run. Had targeted 10:36 based on 73F temp/69F dew point = T+DP of 142 with heat offset of 1.0315, but Garmin claims that the start was only 72F/67F =T+DP 139, heat offset of 1.027 = 10:33. Either way, it was close to 90 by the finish.
Miles 2 - 18 averaged: Pace: 10:30.9, Avg HR: 119.2, using an easy pace cadence of 172.
Drank a ton when I was finished. Took one gel at the start and one at the turnaround. Don't have a clue how I could ever stick some MP miles into the middle of this during the summer.
The 920xt measured 17.94 miles, but I think both of them shorted me some distance. I'll try the 920xt on the edge of my wrist next time.