JWA 2024 Spring Pollen Dispersion Forecast (Part 3)
~Cypress pollen to peak in early April, with full-scale dispersion gradually coming to an end by mid-April~
Press Release
On March 28, 2024, Japan Weather Association (JWA) released its 2024 report on spring pollen dispersion forecasts by prefecture and at national level. Nation-wide forecasts of cedar and cypress pollen will be available excluding Hokkaido, while white birch pollen will be provided for Hokkaido.
1. Peak Period of Cedar and Cypress Pollen
Many areas have already passed the peak of cedar pollen dispersion, including Tokyo and Sendai, which are expected to reach their peak soon. While the peak period typically lasts for about 10 days to a month, Hiroshima and Takamatsu have experienced lower pollen levels this year compared to previous years, resulting in a shorter and less defined peak period.
Cypress pollen has begun to disperse in Kyushu, Kinki, Tokai and Kanto regions, and some areas of southern Tohoku region. Many areas in Chugoku and Shikoku will also see the start of dispersion by the end of March. Warm days in early April are anticipated to accelerate cypress pollen dispersion, leading to a peak in early April across a wide area. The peak period is expected to last approximately one to two weeks. On sunny and windy days, pollen levels tend to rise, so it’s important to take thorough pollen countermeasures. In Sendai, the amount of cypress pollen is expected to be low, with no clear peak expected.
2. How Long will Cedar and Cypress Pollen last?
After the peak of cypress pollen, the full-scale dispersion of pollen is expected to cease shortly in Kyushu through Tohoku. The full-scale dispersion will last until early April in Kyushu and until mid-April in most areas from Chugoku and Shikoku to Tohoku. Parts of the Tokai region may experience dispersion until late April. However, even after substantial dispersion ends, there may still be occasional days with minimal pollen dispersal until early May in various regions. Individuals sensitive to pollen should continue taking precautions during this period.
3. Start of White Birch Pollen Dispersal in Hokkaido
White birch pollen in Hokkaido is expected to begin dispersing in late April. The start of white birch pollen dispersal in Hokkaido tends to be earlier when temperatures are higher in spring (March to May). This year, temperatures in March are expected to be lower than normal, but temperatures in April and May are expected to be normal or higher. Therefore, the start of white birch pollen dispersal is expected to be either normal or earlier than usual.
Pollen Dispersal Forecast:
For more information on pollen dispersal forecast, follow the link below;
https://www.jwa.or.jp/english/service/seasonal-news-pollen-dispersal-forecast/
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Originally released in Japanese: 2024/3/28
PDF DOWNLOAD：JWA 2024 Spring Pollen Dispersion Forecast (Part 3)
