Fall Color Early in Utah
Usually day length drives trees to begin the process of entering dormancy, but weather and tree health also play a role. By early September 2012, high elevation aspens and maples in the Intermountain West had already started turning color, several weeks earlier than in years with typical temperatures and precipitation.
Landscape trees that have not received enough supplemental irrigation, or are under other stresses (insects, diseases, compaction, root loss, etc.) will also show early fall color.
The areas of the country that experienced the worst of the 2012 drought (north-central and midwest) have average fall color due to earlier symptoms of scorch and early drop.
In the northeast, fall color is exceptional and on-time, due to milder effects of the drought, and warm days and cool nights that started in late summer.