When To Expect Peak Fall Colors In Yakima

Today is the first day of meteorological fall, so it it's only naturally to ask: when will we see those beautiful Yakima colors?

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How Color Change Works

During the time of year with peak daylight, trees produce "chlorophyll" to power photosynthesis-the conversion of sunlight into chemical energy. They use the energy to continue to grow throughout the summer.

Chlorophyll gives tree leaves their green color. As night length begins to increase, trees stop producing chlorophyll to save energy for winter. When the tree stops producing chlorophyll, it reveals yellow and orange pigments already present in the leaves called carotenoids.

This process starts at different times of year according to the type of tree. For example, Yakima's quaking aspens begin changing color as early as the last few days of August. Black cottonwoods and willows will begin to see yellows and oranges in early September, red alders mid-month, honey locusts and red maples by the end of the month, sweetgums and flowering plums in early October, and norway maples holding green until the middle of that month.

What About The Effect Of Weather? 

While lack of daylight is the primary driver between color change, cold temperatures do have their role. While leaves are shutting down chlorophyll, they are still being targeted by sunlight which can cause damaging chemical reactions. They put up a red protective shield called an Anthocyanin.

red maple leaves in close up photography

When you have more sunlight, you have stronger reds. Cool nights also slow trees down trapping sugars causing more protective mechanisms producing more anthocyanins.

So When Can I Predict Peak Fall Foliage?

Fall foliage in the city occurs much later than that of tree species near the Yakima River. Leaves don't take long to go from green to peak reds and Yakima should begin seeing its signature peak fall color by roughly October 18. Mid-late October provides perfect fall color viewing conditions.

How Vibrant Will It Be?

Rainy and cloudy weather with warm nights can dull fall colors. However, there is no real way to predict conditions more than 14 days out so we have to stick with the average.

Are you ready Yakima?

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