Quercus buckleyi | Central Valley
Continuing on the theme of within-species variation, here you can see the range of fall color onset in early December in the Central Valley of California. These trees are likely siblings from the same mother, and have a natural range of variation. It is common in the modern urban landscape for fall color to begin simultaneously in all individuals in a tree planting. This is because those trees are clones of a single tree, and behave in unison. That visual uniformity is informed by an underlying lack of genetic diversity, with its attendant ecological vulnerability.