If you live in europe, please check in with your elderly neighbours. Hot temperatures can be deadly for old people
While I do appreciate the information on better infographic creation, the example map has such a small range comparably. There's over 30 values, not to mention the shades in-between values. I think a two color gradient would end up being very smooth at this scale. Sorta looks to generally drop in temperature as you go east here, nice red to blue fade.
Expanding the color palette does give more room for distinction, but that's seemingly how they got where they did.
To be fair, from my friends who've actually had color theory and graphic design classes, STEM folks tend to do a poor job of communicating well.
So eh. Maybe it's pointless for me to argue against it.