How does weather affect fall color?
The amount and intensity of autumn color is related to weather conditions that occur before and during the time the chlorophyll in the leaves is diminishing. Temperature and moisture are the main influences. A succession of warm, sunny days and cool (below 45 F), but not freezing nights brings about the most spectacular color displays.. During these days, lots of sugars are produced in the leaf but the cool nights and the gradual closing of veins going into the leaf prevent these sugars from moving out. These conditions will favor anthocyanin production and brilliant red autumn color. Early frost will weaken the brilliant colors by killing or severely injuring the leaves before the pigments reach their maximum development. Rainy and/or overcast days tend to decrease the intensity of autumn colors due to reduced light intensity limiting photosynthesis and the sugars available for anthocyanin production. The amount of moisture in the soil also affects autumn colors. Soil moisture varies
