Cedar Pollen Forecast 2023 (Part 2):
Cedar Pollen Peak to Start in Nationwide!
Press Release
On Tuesday, March 14th, 2023, Japan Weather Association (JWA) announced the Spring Pollen Dispersal Forecast in each prefecture.
1. Cedar and Cypress Pollen Dispersion
Cedar pollen spread has begun in the wide area from Kyushu to Tohoku (as of March 14th). Pollen dispersion in main areas have started on February 10th in Fukuoka, February 11th in Tokyo, February 18th in Nagoya and Osaka, and February 28th in Sendai. Also, cypress pollen was observed in Yamaguchi on March 1st, in Saga on March 3rd, in Hiroshima on March 9th, in Takamatsu on March 11th, and the dispersal has already begun in some parts of Kyusyu, Chugoku and Shikoku. Both cedar and cypress pollen started scattering 10 days to 2 weeks earlier than in 2022, when the start of scattering was late.
In March, temperatures were higher than normal across the country through the end of last week. In addition, many sunny days with dry air created conditions conductive to the dispersal of pollen.
2. Peak Forecast for Each Location
Cedar pollen has reached its peak over a wide area from Kyushu to Tohoku*. In Tokyo, cedar pollen counts of 500 pollen/cm2 or more were observed for 3 days straight from February 28th, and we are entering the peak of dispersion. Large amounts of pollen dispersal were observed in Tohoku, and cedar pollen counts of approximately 800 to 1,000 pollen/cm2 recorded in Fukushima and Sendai on March 8th. The highest temperatures are expected to remain above normal years, and hay fever sufferers will continue to have a hard time. In Kyushu, the peak, which began in mid-February, is expected to be nearing its end.
In western Japan, the peak of cedar pollen is expected to end soon, but due to the large amount of pollen dispersed this year, it is necessary to take measures against hay fever even after the peak season has passed. In some part of Kyushu, Chugoku and Shikoku cypress pollen has already begun to be dispersed and will continue to peak in various areas from late March to mid-April.
In eastern Japan, cedar pollen will continue to peak throughout March. Since temperatures are expected to be higher than normal years until late March, the peak of cypress pollen in Tokyo is likely to begin in late March. This is earlier than usual and is needed to beware of both cedar and cypress pollen in late March.
* Definition of “the peak of cedar pollen”: the first day of 2 days straight with more than 50 pollen/cm2 is the peak start date.
3. JWA’s Pollen Dispersal Forecast:
For more detailed information about JWA’s Pollen Dispersal Forecast, please find the link below:
https://www.jwa.or.jp/english/service/seasonal-news-pollen-dispersal-forecast/
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Originally released in Japanese: 2023/3/14
PDF DOWNLOAD：Cedar Pollen Forecast 2023 (Mar 14th, 2023)
