I'm not sure the writer understands the project. The route is constructed so that the daily high temperature is 70, so most of the time is spent in sub-70 degree weather. If "69 degrees and below makes you shiver like a soaked kitten", you're SOL.
Way to miss the point. The prose makes it sound like the goal is to maximize the time spent at exactly 70, or to minimize the variation away from 70, neither of which is the case.