The autumnal equinox this year arrives Sunday, Sept. 22. Not only do temperatures typically drop around this time of year, but plant life slows down signaling the changing colors of leaves.

To help chart the changing leaves, the Missouri Department of Conservation offers weekly online fall color updates from agency foresters at mdc.mo.gov/fallcolor.

“Our fall color reports are a convenient resource for the public,” said MDC Forestry Field Programs Supervisor Russell Hinnah. “The reports begin in mid-September and are updated weekly. They show users where trees are beginning to turn and also suggest best places to see the changing leaves.”

Predicting the peak of fall color can be difficult, but much depends on the weather.

“Much of the state is still very dry and we are also still feeling the effects of last year’s drought,” said Hinnah. “With this pattern, we could see an earlier fall with less color. It’s also possible some trees may shut down earlier with no color at all.”

Chilly, fall evenings are critical for leaves to change color.

“Sugars produced by photosynthesis are trapped inside leaves by the cool autumn nights,” Hinnah explained. “Those sugars are the building blocks for the rich red, yellow, orange and purple pigments. Cooler temperatures cause the breakdown of green pigments in leaves, allowing fall colors to show.”

Missouri trees first begin changing color in the northern part of the state, then move southward. Sassafras, sumac and Virginia creeper are some of the earliest to change in mid-September. In late September, black gum, bitterswee, and dogwood begin to turn. The peak of fall color usually hits around mid-October.

“Trees like maple, ash, oak and hickory are at the peak of their fall display by the middle of October,” Hinnah said. “Normally by the end of the month, colors are fading and leaves are falling.”