Heat and drought could change Arizona's autumn leaf season

Warmer nights can delay the changing colors of leaves or turn down their vibrance, scientists say.

Heat and drought are bad combinations for trees, putting stress that could mute autumn colors.

One leaf watcher still expects a good show this fall in the high country, with peak colors in mid-October.

Golden aspens and glowing cottonwoods will soon take over Arizona's high country, drawing hikers and leaf-peepers to the mountains. But the timing and brilliance of the display depend on weather conditions — and with a warming, drying climate, the iconic spectacle is becoming less predictable and sometimes less dazzling.

Warmer nights can delay the shift, leaving a shorter, less vibrant window. Cool nights and sunny days typically bring out the brightest displays. Drought, extreme heat or s