What time zone is Nagoya in?
The city follows Japan Standard Time (JST), a fixed UTC+9 offset. When the sun sits over the prime meridian in Greenwich, London, Nagoya clocks already show 9:00 PM. That gap never shifts. Japan abandoned daylight saving in 1951, so the city keeps UTC+9 in January and July alike.
Japan Standard Time (JST): UTC+9 explained
JST is one of the simplest time zones to work with. No DST transitions. The offset stays nine hours ahead of Coordinated Universal Time.
On 15 January 2026, relative to Nagoya (JST): - New York is 14 hours behind - London is 9 hours behind - Sydney is 2 hours ahead
On 15 July 2026, relative to Nagoya (JST): - New York is 13 hours behind - London is 8 hours behind - Sydney is 1 hour ahead
The difference shifts only because the other cities change their clocks. Nagoya stays put.
Why Nagoya uses Asia/Tokyo (and not Asia/Nagoya)
The IANA Time Zone Database assigns one zone to the whole of Japan: Asia/Tokyo. There is no Asia/Nagoya, Asia/Osaka, or Asia/Kyoto entry.
The database designates a single representative city per region. Tokyo is that city for Japan. Any computer, phone, or server configured for Japanese time uses Asia/Tokyo, regardless of whether it sits in Nagoya, Sapporo, or Fukuoka.
If you are setting up a device or writing code for Nagoya, the correct IANA string is Asia/Tokyo. Do not invent a custom zone. The system works because the entire country shares the same offset and DST rules (none).
The 135°E meridian: Japan's time line
Japan's time is not arbitrary. The 1886 Imperial Ordinance No. 51 fixed the meridian at 135° east longitude. This line passes through the city of Akashi, Hyōgo Prefecture.
The law took effect on 1 January 1888. Before that, cities used local solar time. Nagoya's solar time was slightly different from Tokyo's. The railway and telegraph networks could not function with dozens of local times, so the Meiji government unified the country on the 135°E meridian.
Today, the 135°E meridian is still the legal basis for JST. The meridian itself is marked by a monument in Akashi City, and the line is visible on many Japanese maps.
Solar noon in Nagoya vs clock time
Clock time is based on the 135°E meridian. Nagoya sits at 136.906°E, about 1.9 degrees east of that line. That small difference shifts the sun's position relative to the clock.
Solar noon in Nagoya is approximately 11:48 JST, not 12:00.
The sun reaches its highest point about 12 minutes before the clock strikes noon. In Tokyo, further east at 139.7°E, solar noon is around 11:38 JST. The clock is the same. The sun behaves differently.
For photographers, this matters. The "golden hour" before sunset starts earlier than a clock-based calculation suggests. For farmers and gardeners, the early solar noon means the day's peak heat arrives before lunch.
JST vs other time zone abbreviations
JST is the only official abbreviation for Japan Standard Time. Its Japanese name is Nihon Hyōjun Jikan (日本標準時).
Do not confuse JST with:
- JDT (Japan Daylight Time), this abbreviation appears in some old databases for the 1948-1951 DST period, but it has no official use today. Japan does not observe DST.
- JT (Japan Time), a casual abbreviation, not official.
- KST (Korea Standard Time), also UTC+9, but it is a separate zone (Asia/Seoul).
South Korea and North Korea are on UTC+9, same as Nagoya. China is on UTC+8, one hour behind.
IANA time zone database entry for Nagoya
The IANA entry for Nagoya is identical to all of Japan:
| Field | Value |
|---|---|
| IANA zone | Asia/Tokyo |
| UTC offset | +09:00 |
| UTC offset (DST) | None |
| DST observed | No |
| Last DST transition | 1951 |
The database contains no separate entry for Nagoya. Any application that asks for a time zone should be set to Asia/Tokyo.
How NICT keeps Japan Standard Time
Japan's official timekeeper is the National Institute of Information and Communications Technology (NICT). NICT operates atomic clocks at its headquarters in Tokyo and at the Koganei headquarters.
NICT disseminates JST through: - NTP (Network Time Protocol) servers, used by computers and servers across Japan - JJY radio time signals, broadcast from two stations: one in Fukushima (40 kHz) and one in Kyushu (60 kHz). These signals reach Nagoya and the entire Chubu region.
The legal basis for all of this is the Act on the Standard Time, which defines JST as the time at 135°E longitude. NICT is the agency responsible for maintaining that definition.