Predictions from the 2025 International Cherry Blossom Prediction Competition!

We challenged contestants to predict the day that the cherry trees will reach peak bloom.

We asked contestants to submit their best predictions for select trees in Washington, D.C. and New York City (USA), Kyoto (Japan), Liestal-Weideli (Switzerland), and Vancouver, B.C. (Canada), along with a compelling narrative and reproducible analysis containing any data and code used. The competition is challenging because 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 fourth year in a row, students, researchers, and citizen scientists from around the world accepted our challenge. We will not be able to declare a winner until the cherry trees bloom later this year, but we are excited to share the predictions made by the contestants—as well as their AI competitor.

The predictions are in!

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 reach peak bloom between late March and early April. The average predicted peak bloom dates are March 29th for Liestal-Weideli, March 30th for Washington D.C., March 31st for Vancouver, BC, and April 3rd for Kyoto and New York City—denoted on the calendars by 🌸. For the first time ever, we asked ChatGPT o3-mini-high to produce a model with the aid of our AI handler, Yu-lin Hsu. The AI predictions are denoted on the calendars by 🤖.

Overall, the contestants agree with the National Park Service prediction. 

The National Park Service predicts the peak bloom of the Washington D.C. cherry trees will occur between March 28th and March 31st. A comparable region given by the contestants is also March 28th to March 31st. The contestants disagree with the Washington Post, which predicts an earlier date, between March 23th and March 27th—although this range is consistent with the predictions provided by ChatGPT. 

The contestants disagree with the Japan Meteorological Corporation’s 6th forecast on average, which predicts that the peak bloom of the Kyoto cherry trees will occur on April 6th. (Note JMC provided predictions for Prunus × yedoensis while the contestants predicted Prunus jamasakura. These species have similar but not identical bloom dates.) 

For New York City and Vancouver, BC, where there is almost no historical data, contestants thought that full bloom would be April 3rd and March 31st, respectively. The Vancouver Cherry Blossom Festival posts updates on the stage of their cherry trees on the UBC Botanical Garden Forums.

A big thanks to our sponsors, partners, and judges. 

We thank the American Statistical Association, Washington Statistical Society, George Mason University’s Department of Statistics, and Columbia University’s Department of Statistics and Real World Data Science for their support, and partnerships with the International Society of Biometeorology, MeteoSwiss, USA National Phenology Network, the Vancouver Cherry Blossom Festival, Local Nature Lab, and WSP Eco Projects—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, Mason Heberling, Nathan Lenssen, Will Pearse, Christine Rollinson, and Brittany Sutherland. Thank you! 

Organizers

Judges