Even though cherry blossoms are said to be blooming earlier than they used to, people living in Japan do not necessarily feel that change clearly every year. The cherry blossom front moves earlier in some years and later in others, so people may notice “They’re early this year” or “They’re late this year” more than any long-term trend.
Over a longer period, however, cherry blossoms have been blooming earlier in many parts of Japan. One major reason is that spring temperatures have been rising.
But cherry trees are not as simple as “the warmer it gets, the earlier they bloom.”
Their flower buds spend the winter in a dormant state. After experiencing enough cold weather, the buds begin to wake up. Then, as temperatures rise in spring, their growth continues until the flowers finally open.
In other words, winter cold wakes the cherry buds, while spring warmth moves them toward blooming. If winter provides enough cold and spring warms up early, the blossoms are more likely to open earlier.
That does not mean they bloom earlier every single year. If cold weather continues into early spring, flowering can be delayed. These year-to-year swings are one reason the long-term change can be surprisingly hard to notice in everyday life.
Nor does continued warming necessarily mean cherry blossoms will keep blooming earlier everywhere forever. In warmer areas, winters may eventually become too mild to give the buds enough cold, which could actually delay the process that prepares them to bloom.
Cherry blossoms in Japan are also closely associated with new beginnings. Passing an entrance examination is sometimes described with the expression sakura saku, or “the cherry blossoms bloom,” and full blossoms at school entrance ceremonies are a familiar image.
But if flowering continues to shift earlier, some regions may increasingly see cherry blossoms at graduation ceremonies and fallen petals by the time entrance ceremonies begin. Climate change may gradually alter not only when the flowers bloom, but also the seasonal images that Japanese people have long associated with them.
Cherry blossom timing is not controlled by spring warmth alone. It depends on both the cold of winter and the warmth that follows. The balance between the two helps determine when the blossoms open each year.
