Why are fall colors more brilliant in some years compared to other years?
Fall colors vary from year to year based on weather conditions. Warm, cloudy and rainy fall weather will cause the leaves to have less red color. Well distributed rainfall during the summer and fall will favor a good fall color display. Trees under drought stress will many times drop their leaves without showing much color. Temperature also has an effect. An extreme cold snap will kill the leaves before allowing them to change to their fall display. Heavy rains or high winds will also cause the leaves to drop early.
It’s hard to predict when fall colors will peak, but in general the northern half of Iowa has prime colors during the last week in September to the second week in October. The southern half of the state has prime fall colors during the second to the fourth weeks in October. Learn more about fall colors on the Iowa DNR site.