Clear Skies Delight as Japan Celebrates the Mid-Autumn Full Moon

2024/09/17 20:30 Weather News

Today, September 17 (Tuesday), corresponds to the 15th day of the 8th month of the lunar calendar, and the full moon of the September Harvest Moon has risen into the sky. This year, the Mid-Autumn Full Moon and the full moon do not fall on the same day; the full moon will be tomorrow, one day later.

In many areas along the Pacific coasts of eastern and western Japan, as well as in Hokkaido, the weather is clear, allowing for moon viewing.

From Gifu City, we received a photo capturing the large full moon of the September Harvest Moon rising behind Gifu Castle, which was submitted to Weather News.
» Photos of the sky currently attracting attention

Clear skies for enjoying the full moon

Tonight, a weak autumn rain front is causing clouds in the Tohoku region, and in inland areas, there are still some evening thunderclouds present. In Okinawa and Amami, the sky is also quite cloudy.

In other regions, the clouds are relatively few, particularly in the Pacific coast areas of eastern and western Japan where clear autumn skies are spreading. This photo was taken from Shintomi Town in Miyazaki Prefecture. It’s a perfect evening for moon viewing while enjoying the cool breeze.

If you look closely at the moon tonight, you can see that the lower left side is a bit slim. It will become perfectly round as it approaches tomorrow’s full moon.

The Weather News app has received many moon photos from across the country. Even in areas with a lot of clouds, many people have captured the moon by aiming for gaps in the clouds.
» Live cameras from around the country

What is the Mid-Autumn Full Moon? What is the difference between 中秋 (Chūshū) and 仲秋 (Nakashū)?

The Mid-Autumn Full Moon refers to the moon that can be seen on the night of the 15th of the 8th month in the solar-lunar calendar (lunar calendar) based on the moon’s phases. It is also called the Full Moon of the 15th.

There are two ways to express the sound of “Chūshū”: 中秋 (Mid-Autumn) and 仲秋 (Nakashū). Nakashū often refers to the 8th month of the lunar calendar, while Chūshū typically refers to the 15th day of the 8th month of the lunar calendar.

Originally, the lunar calendar divides the year into four three-month seasons: January to March for spring, April to June for summer, July to September for autumn, and October to December for winter. The 8th month of the lunar calendar represents the middle of autumn, hence the name Nakashū. It is said that while “中秋” (Mid-Autumn) originally had the same meaning, it gradually came to refer specifically to the 15th day of the 8th month of the lunar calendar.

The custom of enjoying the Mid-Autumn Full Moon, which falls in the middle of autumn, was said to have been transmitted from China during the Heian period and remains one of the important festivals in China today, known as the Mid-Autumn Festival.

▼ Sunset and moonrise times in various locations
Nemuro: Sunset at 17:24, Moonrise at 17:08
Sendai: Sunset at 17:41, Moonrise at 17:22
Tokyo: Sunset at 17:45, Moonrise at 17:24
Osaka: Sunset at 18:01, Moonrise at 17:40
Fukuoka: Sunset at 18:22, Moonrise at 18:00
Naha: Sunset at 18:31, Moonrise at 18:06

The Mid-Autumn Full Moon ≠ Full Moon?

Since the lunar calendar is based on the phases of the moon, the days of Mid-Autumn Full Moon and the 15th day may seem to coincide with the full moon, but that is not always the case. In fact, it is more common for the full moon to not fall on the same day.

In the lunar calendar (solar-lunar calendar), days are defined including the moment of new moon as “1st day of the month.” The number of days from new moon to full moon varies from 13.9 to 15.6 days, which means the moment of full moon could occur anywhere from the 14th to the 17th day of the lunar calendar.

This year, the moment of the full moon will occur on the 16th of the 8th month of the lunar calendar, which corresponds to September 18 (Wednesday) in the solar calendar. For the last three years, the Mid-Autumn Full Moon and the full moon occurred on the same day, but the next occurrence of that will be in 2030.

Special program scheduled to be streamed on YouTube

Weather News will provide a live broadcast of the Mid-Autumn Full Moon on the night of the 17th (Tuesday). The special program will feature live images from various locations across Japan, along with tips for enjoying moon viewing.

You can watch the special program and various live cameras from around the country on the official Weather News YouTube channel.

Saturn shines alongside the Mid-Autumn Full Moon

Tonight’s Mid-Autumn Full Moon is in close proximity to Saturn. Throughout the night, Saturn and the moon will move together across the night sky.

Saturn appears bright, similar to Mars, following Venus and Jupiter, but because it is neighboring the bright Mid-Autumn Full Moon, it may be good to observe it with binoculars.

▼ Rise time on the 17th (Tuesday) (Tokyo)
　Saturn: 17:23, Moon: 17:24

Photo: Weather Report (submitted via the Weather News app)

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