"SmokyMountains.com is here to help with its annual Fall Foliage Map. The map uses an algorithm developed from tons of data — like historical temperatures and forecast precipitation from the National Oceanic and Atmospheric Administration — to create a predictive map of when trees will reach peak viewing status around the country. The algorithm then produces a county-by-county breakdown of when colorful leaves are expected to peak that you can toggle through week-by-week. "Similar to any meteorological forecast, leaf predictions will never be 100% accurate," company founder and statistical expert David Angotti said in a statement shared with Travel + Leisure. "However, after publishing our predictive fall foliage map for nearly a decade, we are quite confident in our data sources, process, and algorithm." - Travel + Leisure Editors