Why do sunny days and cool nights create vibrant fall leaf colors?

[Anna Blanksch]

With the leaves starting to change I have been wondering what causes the more dramatic colors verses the more dull leaf colors. I have been told that sunny days and cool nights is the best environment for good autumn colors. If this is true, why does that create the nice colors?

Thanks!

 

[Evo]

With the leaves starting to change I have been wondering what causes the more dramatic colors verses the more dull leaf colors. I have been told that sunny days and cool nights is the best environment for good autumn colors. If this is true, why does that create the nice colors?

Thanks!

For simple things like this, wikipedia is your friend.

http://en.wikipedia.org/wiki/Autumn_leaf_color

 

[Greg Bernhardt]

Warm days and cool nights are exactly what we are getting now. The colors are absolutely spectacular this year!