Japan¡¯s cedar pollen season is expected to begin in early February, with total airborne pollen levels set to exceed historical averages nationwide, according to a forecast released Wednesday by private weather company Weathernews.
According to the forecast, the timing of pollen dispersal is projected to be broadly in line with normal years in western and eastern Japan, while northern regions are expected to see a slightly later start. Nationwide pollen volumes are forecast to be 18% higher than last year¡¯s levels and 28% higher than the long-term average.
Regions that recorded relatively light pollen counts last year ¡ª including Hokuriku, Nagano Prefecture, northern Tohoku and Hokkaido ¡ª are expected to see sharp year-on-year increases, with some areas projected to experience more than double the levels of last year. Akita Prefecture, in particular, is expected to have far higher than usual pollen levels, six times that of last spring.
In contrast, parts of western Japan, particularly northern Kyushu, which experienced record-high pollen levels last spring, are forecast to see lower volumes this year.
Weathernews said small amounts of pollen may already be in the air. Reports of pollen symptoms have already been submitted through the company¡¯s app, particularly along the Pacific coast of western and eastern Japan.
Cedar pollen is forecast to begin dispersing in northern Kyushu, Shizuoka and southern Kanto in early February, spreading across much of western and eastern Japan by mid-February. Northern Tohoku is expected to see the season start by early March. Cedar pollen dispersal is expected to gradually ease after mid-March, while cypress pollen will increase in western and eastern Japan.
Cypress pollen is expected to peak from mid-March to early April, while in Hokkaido, birch pollen is forecast to peak from late April, potentially overlapping with the Golden Week holiday period.
The forecast is based on surveys conducted through the Weathernews app in November and a government survey on cedar flower buds released in December.
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