I was wondering if anyone has seen data on the impact of ambient temperature on performance. Yesterday at 80 degrees F, I rode a run on Rouvy that I've ridden 4 times before. It was a fast 7 mile 5 degree max flat run that works well when I've already worked out hard on outdoor work. My time was 2 seconds off of the same course in April when it was really quite cold here still. House was probably 65 degrees F at that time and probably somewhere above the outdoor temps yesterday (though I didn't look at the thermometer inside, just was saying it's nearly time to run the AC). Since I had two data captures so close, I decided to compare them. My heartrate was much higher yesterday and the training load was 3 times what it was in April. I don't recall the "feeling" from a ride that far back, but usually when I'm working out, it feels hard and I didn't feel much different yesterday.

I can attribute part of the difference to having just cut a couple acres grass on foot (hilly so lots of pulling the mower around) and dragging branches in the hot weather. But still, 3 times the training load seems crazy to me for the same MPH and time. Does heat make that much difference in the output required when riding? It would be interesting to know when comparing data. Like if it's overly significant, it would be silly to try to beat one's own time on a hot day.

The figures don't suggest I was in that much better form in April even though I was still real roads once a day and thus finishing more miles per day.