220 days; a special seasonal day of the microseasons

One things I find to remember in Japan is all the micro seasons and the complex system of the solar calendar. Point in case, today is "220 days", called Nihyaku hatsuka in Japanese, on the old calendar. Which most often falls on September 11th, but in 2025 falls on September 10th as it is 220 days after "Risshun", the first day of spring. 

The "220 days" on the calendar is one of the miscellaneous special days within Japan's micro seasons. There are 72 micro seasons consisting of 24 solar terms. However, there are also 12 miscellaneous special seasonal days known as zassetsu, supplementary solar terms, that are said to indicate the change of seasons. The 220 days is one such supplementary solar term.

Since ancient times, people have believed that typhoons tend to come around this day. Another of the supplementary solar terms, also in September, is 210 days, which fell on August 31st this year (2025), but most often falls on September 1st. Reportedly many farmers still heed the solar calendar. Even if you don't, its a reminder to be alert to typhoons at this time of year.