Meteorology Day

What Is Meteorology Day?

Every June 1st is "Meteorology Day" (気象記念日, Kishō Kinenbi) in Japan. On June 1, 1875, the Tokyo Meteorological Observatory (東京気象台) -- the forerunner of today's Japan Meteorological Agency (JMA) -- began operations on the grounds of the Home Ministry's Geography Bureau in Tameike Aoi-chō (present-day Toranomon, Minato Ward, Tokyo), starting seismic observations that day and three-times-daily weather observations from June 5. The Central Meteorological Observatory established Meteorology Day in 1942 to commemorate this. June 1st is also the JMA's founding anniversary.

Japan's Meteorological Heritage

Meteorological observation in Japan actually began a little earlier, in Hakodate, Hokkaido, in 1872, so Meteorology Day marks the start of the Tokyo observatory rather than the very first observations in Japan. The first public weather forecast followed on June 1, 1884, famously summing up the whole country in one sentence: "Winds throughout the country are variable; the weather is changeable, but tends toward rain." The Central Meteorological Observatory (renamed in 1887) became the Japan Meteorological Agency in 1956. Radio weather forecasts began in 1925, and in 2022 the JMA began issuing forecasts, about half a day in advance, of the possibility of heavy rain from "senjō kōsuitai" (linear rainbands). The JMA today operates about 1,300 automated observing stations (AMeDAS) and provides weather forecasting, warnings, and earthquake and volcano information that are essential to Japan's safety.

Meteorology and Japan's Safety

Weather information is critically important in Japan -- a country where roughly 25 typhoons form in the western Pacific each year, about 11 of them approaching Japan, and which is also subject to heavy snowfall, extreme heat, and heavy rain in the rainy season. The JMA's forecasts, warnings, and "emergency warnings" (tokubetsu keihō, introduced in 2013 for once-in-decades events) are consulted daily by millions of people for everything from daily planning to life-safety decisions.

Fun Facts

• Himawari satellites: Japan's first geostationary weather satellite, Himawari ("sunflower"), was launched in 1977. Today Himawari-8 and -9 observe from about 36,000 kilometers above the equator, providing full-disk images of the Earth every 10 minutes.
• Precipitation probability: Probability-of-precipitation forecasts were introduced in the Tokyo area in 1980.
• Typhoon numbering: In Japan, typhoons are usually referred to by number in order of formation each year -- "Typhoon No. 3" (台風第3号, Taifū Dai-san-gō) -- although international Asian names are also assigned.
• Badge Day: Because "kishō" (meteorology) sounds like "kishō" (badge, 徽章), June 1st is also known as Badge Day.