The art of Japan’s cherry blossom forecast
their entire blooms.
“People pay more attention to the cherry blossom season than any other flower in Japan,” Ryo Dojo, an official of the statistics unit at the Japan Meteorological Agency, said.
The most basic element of predicting when the delicate pink and white petals will begin to unfurl is a large data set of temperatures. That’s because the flowers will come earlier if temperatures rise quickly in spring, Dojo said.
Conversely, if temperatures in the autumn and winter period are higher than usual, the blooms can end up being delayed. Extreme weather can affect trips around the the trees too, with unusual patterns in 2018 prompting some blossoms to appear in October, well before the usual season.
In general, blooms begin as early as March in southern Kyushu and appear as late as May in northernmost Hokkaido.
Sakura project
In a bid to improve its forecasts, some outfits have started crowdsourcing data, including Weathernews, a firm in Chiba near Tokyo. It relies on photos of buds sent in regularly by 10,000 citizens across the country who are registered on the company’s website and app.
“Cherry blossom forecasting is impossible for us without this system,” spokeswoman Miku Toma said. The company launched what they call the “sakura project” in 2004, signing up members who choose their own cherry tree and send pictures of its buds to the firm at regular intervals.
Thanks to the project, Weathernews has accumulated data from two million reports on cherry flower buds in the past 15 years, which it uses to increase the accuracy of its forecasting.
It also incorporates weather data collected from its own observation devices across Japan — 13,000 locations in total, 10 times more than the official weather agency has. Most basic element of predicting when flowers will unfurl is a large data set of temperatures