Inspired by Tyra's workout, did 3 x 1 mile. Not sure it would count as tempo, probably more interval-like. Did them on the Reed track, which is gravel and has a hill.
Times for miles according to my Garmin: 6.30, 5.59, 6.52.
What? Those times are all over the place. And yes, there is a hill on the track, but I'm going around ~4 times, so it's not as if I got all uphill sometimes and all down on others.
What seemed to be the case, and is really strange is that the Garmin thought I was going faster when going clockwise (as seen from above). I have no hypotheses to explain this behaviour, but I'm *sure* my miles were not a minute discrepant.