Maple leaves turn colour when the green pigment chlorophyll, used in photosynthesis, gradually breaks down as the temperature dips below 20 degrees C. The colour deepens as the red pigment anthocyanin is synthesised below 10 deg C.
It is too early to foresee any immediate impact on tourism, beyond illumination events having to be scheduled and tourists having to factor in the delays.
But Ito warned that the New Year can be heralded with autumn foliage: “If summer becomes even longer in future, the best time to see autumn leaves will be delayed even further.”
In 2023, Tokyo is expected to reach peak autumn foliage on Dec 1, which is three days later than average. In the 1950s, such foliage appeared in the city between Nov 8 and 15.
Over in the Nasu Highlands in Tochigi, north of Tokyo, the peak autumn season was forecast for Oct 22. But most leaves were still green at that…
