The leaves have been changing and the colors are starting to peak around the Upper Midwest.
The colors have been somewhat delayed this year and that of course has to do with.... the weather! Here's some information about the color change from the National Weather Service in Central Illinois:
Many people think that cold weather is solely responsible for the color change in leaves, but not so. Leaves begin to turn before we have any frosts. Change in coloring is the result of chemical processes, which take place in the tree as the seasons change.
During the spring and summer, a food-making process takes place in the leaves, within cells containing the pigment chlorophyll. This gives the leaf its green color. The chlorophyll absorbs energy from sunlight, and uses it in transforming carbon dioxide and water to carbohydrates, such as sugars and starch.
In the fall, the decrease in intensity and duration of sunlight, and the cooler temperatures, cause the leaves to stop their food-making process. The chlorophyll breaks down, the green color disappears, and the yellowish colors or other pigments already in the leaf become visible.
Autumn weather conditions favoring the most brilliant colors are warm sunny days and cool, but not freezing, nights. A few hard frosts can cause the leaves to wither and fall from the tree without changing color. The degree of color may also vary from tree to tree. Leaves directly exposed to the sun may turn red, while those on the shady side may be yellow. When warm, cloudy and rainy weather dominates the fall season, leaves tend to have less coloration.
Fall colors usually peak from early to mid October over eastern Iowa and northwest Illinois, to late October in southeast Iowa, west central Illinois and northeast Missouri.
(Picture of fall foliage in Iowa City via Ron Allen, 2018)
There was a slight delay in the colors because of the late onset of the cold. But now the cold has come and it's stayed cold. And it will remain cold as we go through the end of October.
Temperatures are expected to remain below normal into the start of November and the center of that cold is over Iowa and Minnesota! Sunday will be a nice day, though, with plenty of sunshine. Temperatures will near/slightly above normal.
A strong cold front will swing through Sunday night into Monday and bring showers and thunderstorms along with the colder air..
The Fall chill is here to stay. Enjoy the colors while they last!