ST. LOUIS — Autumn officially begins on Saturday, September 23, and soon the vibrant fall colors can be seen. The changing leaves offer a delightful opportunity for leaf peeping, with hues of gold, copper, purple, olive, and auburn to look out for.

Each year, both the previous fall and summer weather conditions have an impact on the timing and intensity of these colors. According to the Smokey Mountains National Park fall foliage prediction map, St. Louis can expect the first signs of color change around the last half of October.

The primary factor influencing the transition in leaf color is the duration of daylight. Typically, St. Louis witnesses peak colors during the last week of October or the first week of November. However, due to the diverse range of tree species in Missouri, each changing at different rates, the fall color season can extend for 4 to 6 weeks. Weather conditions can accelerate or delay this schedule by about a week or two.

But why do leaves change color?

The process relies on cooler nights, as the chlorophyll responsible for the green color in leaves diminishes when trees prepare for winter dormancy. As chlorophyll decreases, other underlying pigments emerge, revealing the red, orange, and gold shades.

Summer heat stress and drought can affect the vibrancy of fall color. To enhance the chances of brilliant fall foliage, the ideal autumn weather includes sunny days, allowing trees to continue producing food, and gradually cooler nights. A sudden early freeze can curtail the fall color season, damaging leaves before they fully transform.

Where can St. Louis residents go leaf-peeping?

The Missouri Department of Conservation recommends exploring local parks for prime leaf-peeping spots.

Consider routes that run alongside rivers, offering views of lush, forested bluffs, or opt for paths along ridges with expansive vistas of wooded landscapes. Explore the back roads, embark on hikes, or enjoy a serene float trip on clear days.

Even in treeless environments like prairies and roadsides, leaf-peepers can appreciate the natural beauty of autumn through the array of wildflowers, shrubs, and prairie grasses. If traveling outside the city isn’t an option, check out trees in locations such as historic neighborhoods, parks, and even cemeteries.