When the days start getting shorter and the leaves begin to fade from the vibrant green of spring and summer to lovely hues of yellow and red, you know fall is around the corner. Mr. MORECAST looks into the process of why leaves change color and what to expect this upcoming fall season.
Why Fall Leaves Change Color
People often associate the changing of leaf colors with changes in the weather. However, the weather plays only a minor part in the process.
During the spring and summer months, photosynthesis occurs in plants and trees. At this time, plants and trees create excess chlorophyll to help retain the green coloring necessary for continued intake of nutrients.
As fall approaches and the length of night increases, the tree goes into hibernation mode. Chlorophyll production ceases since there isn’t enough sunlight through the winter months for photosynthesis to effectively take place.
This reduction in chlorophyll causes the leaves to become more fragile with the yellow and orange color pigments more exposed. Hence, the decrease in sunlight in the fall months is the main cause of the changing colors.
Timeline of Peak Foliage
Peak foliage varies across the country, with the earliest change of colors seen in the northern states and higher elevations. The high peaks of the Rocky Mountains, Appalachian Mountains, and Northern Great Lakes experience a peak foliage by late September-early October.
As you drop in elevation across the Plains, Northeast, and Intermountain West, expect an average peak foliage in mid to late October. Along the coast and deep South, peak conditions occurs in late October to early November.
Weather’s Impact On The Fall Foliage
Although decreasing sunlight is the main cause of fall foliage, weather does have a small impact on the changing leaves.
Temperature, sunlight, and precipitation each affect how long the hues of orange and red last throughout the fall. Rain leads to an increase in soil moisture, preventing the leaves from drying out. Sunny days, rather than overcast, lead to increased amounts of chlorophyll in the leaves. Hence, the best weather conditions consist of adequate rainfall and ample sunshine during the spring and summer months.
Towards late summer and fall, moist soil, lack of severe storms, sunny days, and cool, frost-free nights are best-suited for sustaining peak foliage.
MORECAST’s Fall Outlook
Will this year’s fall weather help fall foliage stick around longer than normal?
Above normal temperatures in some regions of the country could decrease the amount of frost events, leading to a longer duration of changing leaves. Warmer than average temperatures in the Eastern and Western US will make conditions favorable for a slightly longer duration of fall foliage. Elsewhere, the Central US, Upper Midwest, and Northern Plains forecast calls for near normal temperatures.
Residents in the interior Northeast, Ohio River Valley, Deep South, and Western US can expect below normal rainfall this fall. The seasonal forecast suggests little relief for drought stricken areas in the West. Above average rainfall is forecast for parts of the Northern Plains and Upper Midwest while the central portion of the country remains near average.
Drought Conditions
Over the last several months, drought conditions persisted across parts of the Northeast, Southeast, Northern Plains, and Western US. Despite the drought, fall colors will not be affected over the East and West. After a similar drought back in 2012, bright colors still prevailed for much of the fall season.
Fall Foliage Forecast
With the current cool nights and ample sunshine, leaves are turning ahead of schedule. However, with the forecast showing above average temperatures and lack of rainfall in the Eastern and Western US, it will be tougher to find the brightest colors.
The best colors will occur in river valleys, high peaks, and near lakes across the West and Northeast. Across the Central US, the lack of a significant drought and near normal temperatures will allow for a normal color change, with brighter colors more easy to find.
Capture a good picture of the changing leaves? Upload your fall foliage pictures to the MORECAST app!