There are many factors that determine when leaves change their colors and how vivid the result.
The best fall color occurs when days are bright, nights are cool, and soil moisture is good, said Mary McClelland, a horticulturist and co-owner of McHenry County Nursery, Inc. in Harvard.
“It almost seems like the colors are changing overnight,” she said “Fall color depends on many things. In this Midwest area, we have had a variety of moisture levels in late summer and early fall and that affects color. There could be good fall color in one area and then 30 miles north or south, not so good,” McClelland said.
With the warmer temperatures and brighter days we certainly are setting up for good fall colors,’ McClelland said.
Ed Hedborn, known as the Morton Arboretum's ‘Color Scout,’ is predicting a vibrant fall.
"Fall color is still in the early stages, but the recent rain, along with sunny days and cool nights seem to be stimulating brighter fall color development,” Hedborn said in his weekly color update on the Morton Arboretum website.
This autumn is also turning out to be a pleasant one in which to spend time outdoors enjoying the changing colors.
“We’ve got a really nice front and folks who like warm fall weather will be very happy,” said Ed Fenelon, meteorologist for the National Weather Service's Chicago office. The Chicagoland area could see 80s by the end of the week.
“It’s typical in fall to get a nice dry spell with warm temperatures during the day and cool at night,” Fenelon said.
Fenelon said the first half of October is expected to be warmer than normal.
The warmer weather may provide a good opportunity to explore the McHenry County Conservation District sites.
“Maples turn earlier than oaks and hickories. With that being said, the colors at Coral Woods Maple Sugar Loop trail in Marengo will be about a week earlier than the oak savannas at Glacial Park in Ringwood, which coincidentally usually hit their peak the third weekend in October during Trail of History weekend, which is another reason for people to come out to the event,” said Kim Compton, MCCD education program coordinator.
As for the weather outlook later this fall and winter, it is a La Niña year, Fenelon said.
“In a La Niña pattern, there are mild periods followed by cold outbreaks, and snowy weather. There is a higher than normal risk of severe weather, like the tornadoes we had in November last year,” Fenelon said.
La Niña is a naturally occurring climate phenomenon located over the tropical Pacific Ocean and results from interactions between the ocean surface and the atmosphere, according to the National Oceanic and Atmospheric Administration website.
Cooler-than-average Pacific Ocean temperatures influence global weather patterns. La Niña typically occurs every three-to-five years, and back-to-back episodes occur about 50 percent of the time. The NOAA reports that current conditions reflect a re-development of the June 2010-May 2011 La Niña episode.