Cherry blossom front

From 1951 the Japan Meteorological Agency produced forecasts for the Kantō region and from 1955 for the whole of Japan excepting Okinawa and the Amami Islands.^[1] From 2010, the Agency left forecasting to the private sector although it continues to observe and determine the impact of the climate upon the flowering of the cherry.^[2][3] The forecast is based on the Arrhenius equation, with the formula $${\displaystyle {\text{DTS}}=\exp \left[9.5\times 10^{3}\cdot {\frac {T-288.2}{288.2\,T}}\right],}$$  where T is the mean day temperature in kelvins, and DTS represents the number of days transformed to standard temperature.^[4][5][6]

The day of opening^{[note 1]} is defined as the point at which at least five to six flowers have opened on the sample tree. The day of full bloom is when at least 80% of the flowers have opened. The Yoshino cherry is typically observed since, from the late Edo period, it has been planted across the archipelago.^[7] Sample trees also include the Higan cherry in the south and Prunus sargentii (Sargent's cherry) in the north.^[7]

In 2006 it was reported that the cherry blossoms might overtake the plum blossoms before reaching Hokkaidō.^[8]

 

There are fifty-nine sample trees at any one time. Successor junior trees are selected from among prospective candidates when an incumbent becomes too old or is otherwise incapacitated.^[3] For instance, the sample tree in Mito collapsed under the weight of snow in 2005, while that at the southern tip of Ishigaki Island was felled by a typhoon a year later.^[3] The fifty-nine sample trees are located across Japan, corresponding to the sites of the Agency's principal weather stations:^[10][11][12]

• Okinawa: Ishigaki, Miyako-jima, Naha, Minamidaitō
• Kyūshū/Yamaguchi: Fukuoka, Shimonoseki, Ōita, Nagasaki, Saga, Kumamoto, Miyazaki, Kagoshima, Amami (formerly Naze)
• Shikoku: Takamatsu, Tokushima, Matsuyama, Kōchi
• Chūgoku: Hiroshima, Okayama, Matsue, Tottori
• Kinki: Ōsaka, Hikone, Kyōto, Maizuru, Kobe, Nara, Wakayama
• Tōkai: Nagoya, Shizuoka, Gifu, Tsu
• Kantō: Tōkyō, Mito, Utsunomiya, Maebashi, Kumagaya, Chōshi, Yokohama, Nagano, Kōfu
• Hokuriku: Niigata, Toyama, Kanazawa, Fukui
• Tōhoku: Sendai, Aomori, Akita, Morioka, Yamagata, Fukushima
• Hokkaidō: Sapporo, Wakkanai, Asahikawa, Abashiri, Obihiro, Kushiro, Muroran, Hakodate.

• Leaf peeping
• Ueno Park

• (in Japanese) 2012 day of opening (JMA record)
• (in Japanese) 2012 day of full bloom (JMA record)
• (in Japanese) 2011 day of opening (JMA record)
• (in Japanese) 2011 day of full bloom (JMA record)
• (in Japanese) JMA flowering data, 1953–2010