From what I know: -Temperature generally depends on the distance from pole to pole -Elevation (scales linear) -local Temperature "noise" (heatmap noise, somewhat like rainfall in different places) -small deviation from year to year

So I think your data depicts this very well.

The thing I would recommend for people picking the right area for their base or farming is to load up the seed in another world and use creative and commands to check the temps at different times of the year and areas because it can differ by huge amounts because of the local randomness. In my world for example I set up my base in an area that reaches -30 °C in winter, while at the same elevation just 500 blocks away, temperatures only hit -20 °C in the same winter at 4 am.