| Holiday Name: | Autumnal Equinox Day |
| Type: | Public |
| Observedby: | Japan |
| Significance: | Commemorates the autumnal equinox |
| Date: | September equinox |
| Date2010: | September 23 |
| Date2011: | September 23 |
| Date2012: | September 22 |
| Date2013: | September 23 |
| Date2014: | September 23 |
| Date2015: | September 23 |
| Frequency: | annual |
| Duration: | 1 day |
| Celebrations: | family reunions, outdoor activities, snacks such as botamochi |
is a public holiday in Japan that usually occurs on September 22 or 23, the date of Southward equinox in Japan Standard Time (autumnal equinox can occur on different dates for different time zones). Due to the necessity of recent astronomical measurements, the date of the holiday is not officially declared until February of the previous year. Autumnal Equinox Day became a public holiday in 1948. In 1947 and before, it was the date of, an event relating to Shinto. Like other holidays, this holiday was repackaged as a non-religious holiday for the sake of separation of religion and state in Japan's postwar constitution.
On this day, people will reconnect with their families by tending to the graves of ancestors and visiting shrines and temples. People also celebrate the good weather and autumn harvest by enjoying outdoor activities and eating Shūbun no Hi snacks such as botamochi– a ball of sweet rice in azuki paste.