TOKYO – Japan’s picnic calendar has been thrown into confusion as spring cherry blossom appears likely to bloom in the north at the same time as, or even ahead of, plum blossom, which normally appears in January and February.

The two events are usually enjoyed in very different atmospheres by different kinds of people. But a cold winter has made plum blossom two months late in northern cities such as Sendai.

Forecasting blossom is a serious business, as companies organize bonding picnics based on the predictions while shrines schedule festivals for the most auspicious days.

Weather forecasts focus primarily on the “cherry blossom front line,” which shows the advance of the blossom from Kyushu, in the warm south west, to chillier Hokkaido, 1,000 miles north.

This year, a warm spring has seen the cherry blossom front line race up Japan, closing in on the slower moving plum blossom.

One newspaper reported yesterday on the “race to the north,” asking “which will reach Hokkaido first?”

Cherry has overtaken plum only once in the past 20 years.

Plum trees are smaller than the famed sakura cherry but are appreciated for their delicate white and sometimes crimson flowers. Cherry trees produce profuse pink blossom, which some plum fans find showy.

But most Japanese prefer cherry blossom because it heralds the arrival of spring.