TIL: The yellows and oranges in fall foliage are what's revealed once leaves stop photosynthesizing, but the red is something that plants specifically make, and scientists aren't entirely sure why or for what. Possibly a sunscreen of sorts.
Anyway, that red is missing from a lot of foliage in recent years, and that's because it needs cold nights to make it pop.
https://www.wbur.org/news/2024/11/07/climate-change-fall-foliage-science-new-hampshire