Wet weather means early fall colors
Leaves have already started to change in northern Wisconsin and could reach their peak as early as the third week in September, according to a Fall Foliage Prediction Map from SmokyMountains.com. That’s about a week earlier than they normally peak in that part of the state.
The booking website’s interactive map predicts when fall colors will peak in every county in the country, based on several million data points, including National Oceanic and Atmospheric Administration historical and forecast weather, when leaves have peaked in the past and current observations.
According to the map, colors should peak in southern Wisconsin around Oct. 1. They don’t usually peak in that part of the state until mid- or late October.
“Due to the heavier precipitation throughout the summer months, this year’s leaf model is predicting an earlier-than-typical peak fall,” said Wes Melton, the map’s creator. “However, the NOAA 90-day future precipitation and temperature graphs point to a prolonged color period for much of the country.”
Travel Wisconsin’s map predicts peak color in northern Wisconsin to come the first week in October and the third week in October in Milwaukee County.
The main factor that causes leaves to turn is shorter days. As daylight decreases, leaves stop producing chlorophyll, allowing their true colors — orange and yellow, caused by carotenoid pigments in the leaves — to shine through.
Weather can also play a role in the changing leaves. A drought can delay the arrival of colors. An early frost or heavy winds can cause them to drop early. According to the Wisconsin Department of Natural Resources, the best recipe for prime fall colors is a warm, wet spring; a summer that’s not too hot or dry; and a fall with warm, sunny days and cool, but not freezing, nights.
This year’s early changers are not necessarily a good thing.
“Our folks have said that the early color that they’ve seen is due to the water-level stress, so the fact that we’ve had so much moisture this season,” said Kirsten Held, a forestry outreach and education specialist with the DNR.
Wisconsin saw an average of
25.25 inches of precipitation from January through July —
7.14 inches above average. That’s the most in the 123 years data have been collected.