September 25 is the mid-autumn moon celebration in Japan. The National Astronomical Observatory of Japan (NAOJ) places this year’s astronomical full moon two days later, on September 27 at 01:49 JST.
中秋の名月 Chūshū no meigetsu The mid-autumn moon
中秋 (chūshū) names the middle of autumn in the traditional calendar. 名月 (meigetsu) means a celebrated or beautiful moon. This moon-viewing observance does not always fall on the astronomical full moon.
The cultural calendar and the sky can keep slightly different time.
Practice: 今夜は中秋の名月を眺めたい。 Kon'ya wa Chūshū no meigetsu o nagametai. Tonight I'd like to admire the mid-autumn moon.
Source: National Astronomical Observatory of Japan (NAOJ) https://www.nao.ac.jp/astro/sky/2026/09-topics03.html