"It's officially fall in the Northern Hemisphere, which means bright, beautiful foliage isn't far behind.

Parts of the U.S. will soon start to see — if they haven't already — leaves and shrubs trade their green hues for vibrant shades of orange, yellow and red as the days get shorter and temperatures get chillier.

"It's a really cool process that we get to watch, that trees are preparing for winter," says Alexandra Kosiba, extension assistant professor of forestry at the University of Vermont."

Rachel Treisman reports for NPR September 22, 2025. [2]