Does a higher temperature mean higher rankings?

No. Nothing here predicts a ranking, a click or a sale, and any tool telling you otherwise is guessing with more confidence than the data supports.

Two pages at 68 degrees can perform completely differently, because what separates them is competition, demand, and whether the writing is worth reading. None of those are visible from a fetch.

What the number is good for: deciding whether to look closer, comparing two pages on the same basis, and watching one page change over time.