I ran a 5k TT on the track 4-weeks ago in 19:14 (it was an actual 5K--no GPS). This morning, I did a TT on a real course and was slightly disappointed to run 20:39 (although this is 1-minute faster than my previous PR for this course). The track time trial had great weather and was run at noon, while this morning I ran at 7 AM with a temperature/dewpoint reading of 75/74. The course has 250' of elevation gain. Are these comparable efforts?