JST — Japan Standard Time
Japan standard time (UTC+9, no DST).
JST stands for Japan Standard Time. Japan standard time (UTC+9, no DST).
JST is UTC+09:00 from Coordinated Universal Time (UTC). The primary IANA zone is Asia/Tokyo.
JST is used year-round without daylight saving adjustments.
Countries using this zone
- Japan
- South Korea
- North Korea
- Palau
- East Timor
- Indonesia
- Russia
Principal cities
- Tokyo
- Yokohama
- Osaka
- Nagoya
- Sapporo
- Fukuoka
- Kawasaki
- Kobe
- Kyoto
History
Japan officially adopted the 135°E meridian as the basis for its standard time in 1886, a change that took effect on 1 January 1888. The nation briefly experimented with daylight saving time between 1948 and 1951 during the occupation period but discontinued the practice due to public opposition. Since that time, Japan Standard Time has remained a fixed year-round offset without any seasonal adjustments or recent changes to its IANA tzdata status.
Frequently Asked Questions
JST — Japan Standard Time. Japan standard time (UTC+9, no DST).
JST is UTC+09:00 year-round.
Countries and territories primarily using JST include: JP.
JST is used year-round without daylight saving adjustments.
The primary IANA time zone representing JST is Asia/Tokyo. Operating systems and programming libraries use this identifier to resolve local time.
Japan Standard Time is the official time zone for Japan, maintaining an offset of UTC+9. It is used consistently across the entire nation, including the four main islands and numerous smaller islands. Because the country does not utilize seasonal clock changes, JST remains the standard for all administrative and social functions year-round.
Japan does not currently observe daylight saving time. While the practice was briefly introduced during the late 1940s, it was discontinued after a few years. Recent discussions regarding the reintroduction of seasonal time changes, particularly to address energy consumption or summer heat during international events, have not resulted in any permanent policy shifts.
Japan Standard Time is exactly 9 hours ahead of Coordinated Universal Time. When it is noon at the Prime Meridian in Greenwich, it is around 9 PM in Japan on the same day. This fixed offset makes it easy to calculate time differences for international business and travel without accounting for seasonal adjustments.
Several of the largest metropolitan areas in the world operate within Japan Standard Time. These include Tokyo, the national capital, along with other major urban centers like Yokohama, Osaka, Nagoya, and Sapporo. Because the entire country occupies a single time zone, there is no time difference when traveling between these major cities.
JST is exactly 9 hours ahead of Greenwich Mean Time. Historically, GMT was the primary reference, but modern systems now use Coordinated Universal Time for greater precision. Since Japan does not use daylight saving time, the gap between London and Tokyo changes from 9 hours to 8 hours when the United Kingdom observes summer time.