

Depends how high into the triple digits, whether there’s shade and water available, how humid it is, whether air conditioning is an option, etc.
I would probably choose triple digits. I do love cold winters, but a dry 104F with a cool place to swim and big, shady trees is splendid. Beyond about 110F gets miserable, though.
I’ll bet the lane is there purely to satisfy some requirement for including non-car infrastructure, regardless of whether it makes sense in this particular location. It’s the same way we get fun bike lanes like these: