March 7, 2025
Video: Predicting when cherry trees will bloom on UW campus
The University of Washington invites the community to enjoy the iconic Quad cherry blossoms on campus this spring. The 29 cherry trees in the University of Washington Quad usually draw large crowds on campus and reach peak bloom the third week of March, and this year is on track to meet that timing.
Warmer temperatures and mild weather affect when the cherry trees start to blossom and when they reach peak bloom. The UW’s Bloom Watch is updated regularly to reflect the current blossom phases, including when peak bloom is expected.
The UW’s iconic Yoshino cherry trees typically bloom March through April, but forecasting the precise dates for prospective visitors is an annual challenge. To refine the prediction, a UW research group is using historical weather data going back to 1966 and student-collected observational data to come up with the timing of peak bloom — and looking at how a warming climate impacts that date. Once the trees reach peak bloom — when at least 70% of the blossoms have emerged — cooler temperatures, dry weather and low wind will keep the blossoms on the trees longer.
“We found that in Seattle, because our winters are so mild and warm, there’s actually been a delay in the bloom time over the past six decades,” said Autumn Maust, a UW doctoral student in the School of Environmental and Forest Sciences. “The bloom time is shifting a little bit later.”
This is because cherry trees need to accumulate both chilling and warming units — accrued over springtime periods of cool and warm temperatures — to reach a threshold that forces them through the bloom stages. Mild winters, Maust says, mean it takes longer to reach the required chilling units.
There are dozens of varieties of blossoming cherry and plum trees across the Seattle area, with blooms for some species visible from early February until May. Bloom colors range from white to light rose to dark pink, and cherry trees — unlike plums — have distinct horizontal-line patterns on their bark called lenticels. These help the trees “exhale” or release carbon dioxide and water.
But you need not wait for peak bloom to visit campus, the season is underway. The UW maintains a visitors’ website dedicated to updates on the status of the blooms as well as details on transportation, activities and amenities. The Quad cherry blossoms also have their own social media accounts on Instagram and X. Cherry tree enthusiasts who can’t make the trip can keep up with UW Video’s live webcam overlooking the Quad, a virtual tour with photos from campus and tweets from @uwcherryblossom.
###
For more information or to schedule an interview, please contact Dana Robinson Slote: drslote@uw.edu or 206.457.6058
Tag(s): Autumn Maust • cherry blossoms
