As fall approaches, residents in Illinois and Massachusetts are beginning to notice changes in leaf colors. The official start of fall is on September 22, but signs of color transformation are already visible in some areas.

In Illinois, particularly in the northern region, leaves are showing minimal signs of change. According to the state's fall foliage map, the transition will gain momentum by the end of September. The Illinois Department of Natural Resources anticipates that by early October, colors will start to shift across much of the Midwest. By October 15, moderate color changes are expected in northern Illinois, with further spread into central areas by October 20. Peak foliage is projected to occur between the second and final weeks of October, especially in locations like Galena, Chicago, and Starved Rock.

By late October, peak colors will typically persist in the Chicago area, but northern Illinois will begin to enter the "past peak" phase. Central Illinois will experience peak colors slightly later. As November arrives, most leaves will have passed their peak.

Several factors can influence the timing and vibrancy of fall colors. Cooler temperatures and shorter days trigger the breakdown of chlorophyll in leaves, leading to color changes. Meteorologist Kevin Jeanes noted that a hot and dry summer can diminish the brightness of leaf colors. Research from Morton Arboretum indicates that trees respond to prolonged extreme weather conditions rather than short-term heat waves.

In Massachusetts, the fall season is also showing early signs of color. As of mid-September, residents can expect to see partial color on trees. The most noticeable changes are anticipated between September 27 and October 4, particularly in southern New England. The peak foliage period in the Berkshires is expected from October 4 to October 15, while the Pioneer Valley will see peak colors from October 15 to October 25. By November 1, western Massachusetts will generally be past peak, with trees typically losing their leaves by November 15.

Both states are gearing up for a vibrant fall season, with the timing of peak colors influenced by weather conditions leading up to the season.