Why Do Leaves Change Colour in Autumn?

September 23rd begins the autumn

As summer ends and autumn begins, the days get shorter and shorter. With fewer daylight hours, leaves are not able to make as much chlorophyll as they can during the long daylight hours of spring and summer. As the chlorophyll fades, we are able to see other colours, such as orange and yellow, emerge.

Many people mistakenly believe that weather makes leaves change color. While this is not true, weather can affect how vibrantly the colours appear.

If the weather is too hot or cold, the leaves will not be as bright as they begin to change. The best weather for brilliant autumn foliage is sunny, warm days and cool nights.

Water also plays an important role in autumn leaf colours. If a tree doesn't receive enough water, the leaves will die faster and fall to the ground. If there is too much rain, the tree won't receive enough sunlight, and the leaves will not be brightly colored.

You may be surprised to learn that each leaf has small amounts of other colors in it year-round, even if we can't see them. During the spring and summer, chlorophyll overpowers the other colours, and all we see is green. With less chlorophyll to give the leaf its vibrant green colour, we begin to see the other colours, such as orange, yellow, and red, which have been there all along.