2023 blossom prediction entries are in

The predictions are in!

We challenged students, researchers, and citizen scientists to predict the peak bloom date of cherry trees at four locations around the world in 2023: Washington D.C., USA; Kyoto, Japan; Vancouver, Canada; and Liestal-Weideli, Switzerland. While it is known that cherry trees tend to bloom earlier each year as climates warm, complex weather patterns make annual predictions extremely difficult.

For the second year in a row, contestants took up our challenge to build statistical models that produce accurate and interpretable predictions. Their entries are eligible to receive prizes of $5,000 or more. In addition, their work will help scientists better understand the impacts of climate change.

We gave contestants all the publicly available data on the bloom date of cherry trees we could find. (Many of the locations are represented on this map.) The contestants combined this data with other publicly available data (e.g., climate data) to make their predictions.

Contestants vary widely in their predictions for 2023.

The calendars below show the days the contestants predict the peak bloom date will occur. Some believe peak bloom will occur in early March, while others believe it will occur in early May. When the entries are combined, the overall consensus is that the cherry trees will bloom between late March and early April. The average predicted peak bloom dates are April 4th for Kyoto, April 5th for Liestal-Weideli and Vancouver, and March 28th for Washington D.C.—denoted on the calendars by 🌸.

The contestants largely agree that the cherry trees will bloom between late March and early April. (The dark blue squares denote bloom days with high probability according to the entries, while the light blue squares denote bloom days with low probability. The probability was determined by approximating the histogram of days predicted by the contestants with a normal distribution.) The contestants agree the most about the bloom date of the Washington D.C. location and the least about the bloom date of the Liestal-Weideli location.

Overall, the contestants believe the National Park Service prediction is too early.

The National Park Service predicts the peak bloom of the Washington D.C. cherry trees will occur between March 22nd and March 25th. The Washington Post predicts a later date, between March 25th and March 29th. On average, the contestants agree with the Washington Post, predicting peak bloom will occur between March 26th and March 30th.

Who will win the 2023 International Cherry Blossom Prediction Competition?

Stay tuned! We hope to announce the winners in early May. We will also announce the winners for best narrative. We thank the contestants for their hard work. In addition, a big thanks to Posit, the American Statistical Association, Caucus for Women in Statistics, George Mason University’s Department of Statistics, and Columbia University’s Department of Statistics for their support, and partnerships with the International Society of Biometeorology, MeteoSwiss, USA National Phenology Network, and the Vancouver Cherry Blossom Festival—as well as Mason’s Institute for Digital InnovAtion, Institute for a Sustainable Earth, and the Department of Modern and Classical Languages. We also thank our judges Lelys Bravo de Guenni, Cheryl Brooks, Rebecca Forkner, Mason Heberling, Nathan Lenssen, Will Pearse, Christine Rollinson, and Ed Wu.

Sponsors

Logo of the American Statistical Association
Logo of the Department of Statistics at George Mason University.
Logo of the caucus for Women in Statistics
Logo of the Department of Statistics at Columbia University

Partners

USA National Phenology Network