NewsMontana and Regional News


Fall Foliage: The Science Behind the Colors

Plus an update on peak dates throughout Montana
Posted at 10:48 AM, Oct 01, 2021

Fall foliage season is a time many of us look forward to, especially after this summer's persistent heat. The process actually begins as we start losing daylight throughout the summer months.

As cooler weather begins in September and October, the chemical chlorophyll which gives plants their green color and provides sugar for the tree to grow begins to break down. This actually leaves behind the natural colors found in the tree, such as carotene and xanthophyll.

Carotene is the color that makes carrots orange and xanthophyll makes bananas or squash yellow. What you are seeing is the unveiling of the tree's natural leaf color.

The summer's weather dictates the vibrancy of the Autumn leaves. A dry late summer with cool nights is ideal for brighter colors and we have seen just that in north-central Montana. Although the days have been hot, the cool nights and drier weather will provide us with vibrant fall colors as we head towards peak.

Currently, Great Falls and Helena are days away from peak. This should occur this weekend into next week. Location such as Bozeman and Glacier National Park have already reached peak and will be moving past peak heading into next week.

Now is the time to get your leaf-peeping in and if you can, snap a photo and send it our way! You can send it to the StormTracker Facebook page or to