Are those temps ambient or ground?
As you know there is a big difference which often times throws people off.
So far, I haven't been able to find a definitive answer for that chart, but I'm assuming ground; ambient, unless indoors and controlled, would be changing, sometimes wildly, constantly.
That's based on the fact that most planting instructions which mention temperatures specify minimum soil temps to sow; and on what I know of recommended bottom heat temps for germinating tomato & pepper seeds.
Also, that would have to be temperature at planting depth; otherwise it would not affect the seed.
Ambient temperatures affect the growth rate, blooming, pollen production, and fertilization of blooms.
For example, when it's too hot, the pollen tubes in corn silks shrink, and the pollen is blocked from reaching the embryonic kernels; also, at around 96F, nearly all varieties of corn stop growth, and just sit there doing nothing but surviving.
Hardiness zone only refers to average winter minimum ambient temperature but don't consider length of growing season, the maximum summer temperatures, the normal humidity ranges, or wind patterns. It's only a guide to winter survival of an established plant that is in the ground, not a container.
The temps are soil temps, not ambient.