What is JST in AST?
Atlantic Time is 12 hours behind
Japan Standard Time is on UTC+9:00 and Atlantic Time is on UTC−3:00 right now. Atlantic Time is on daylight saving, so its clocks read ADT. The gap changes during the year — see below.
- Time in Tokyo
- 9:52:29 PM
- Time in Halifax
- 9:52:29 AM
- Difference
- −12 h
- Next clock change
- November 1, 2026
Convert a time
ADT — Atlantic Time
9:00 am
ADT, Fri
When the difference changes
Japan Standard Time and Atlantic Time do not change their clocks on the same dates, so the gap between them is not the same all year. Most converters show only today’s figure. These are the periods ahead:
- Now – November 1, 2026Atlantic Time is 12 hours behind
- November 1, 2026 – March 14, 2027Atlantic Time is 13 hours behind
- March 14, 2027 – onwardsAtlantic Time is 12 hours behind
Periods shorter than a day are not listed. Each zone changes at its own local time, so on a date when both move there are a few hours when the gap is briefly something else.
Daylight saving
Japan Standard Time
Japan Standard Time stays on JST all year, so its offset from UTC never moves.
Atlantic Time
Clocks go back one hour — 2:00 am becomes 1:00 am local time, and the zone is on AST after that.
JST to AST conversion table
Every hour of Friday, September 25, 2026, converted from Japan Standard Time to Atlantic Time. 12 of the 24 hours fall on a different calendar day in Halifax, which is marked.
- 12:00 am JST
- 12:00 pm ADT−1 day
- 1:00 am JST
- 1:00 pm ADT−1 day
- 2:00 am JST
- 2:00 pm ADT−1 day
- 3:00 am JST
- 3:00 pm ADT−1 day
- 4:00 am JST
- 4:00 pm ADT−1 day
- 5:00 am JST
- 5:00 pm ADT−1 day
- 6:00 am JST
- 6:00 pm ADT−1 day
- 7:00 am JST
- 7:00 pm ADT−1 day
- 8:00 am JST
- 8:00 pm ADT−1 day
- 9:00 am JST
- 9:00 pm ADT−1 day
- 10:00 am JST
- 10:00 pm ADT−1 day
- 11:00 am JST
- 11:00 pm ADT−1 day
- 12:00 pm JST
- 12:00 am ADT
- 1:00 pm JST
- 1:00 am ADT
- 2:00 pm JST
- 2:00 am ADT
- 3:00 pm JST
- 3:00 am ADT
- 4:00 pm JST
- 4:00 am ADT
- 5:00 pm JST
- 5:00 am ADT
- 6:00 pm JST
- 6:00 am ADT
- 7:00 pm JST
- 7:00 am ADT
- 8:00 pm JST
- 8:00 am ADT
- 9:00 pm JST
- 9:00 am ADT
- 10:00 pm JST
- 10:00 am ADT
- 11:00 pm JST
- 11:00 am ADT
Scheduling between the two
There is no overlap between a nine-to-six working day in Tokyo and one in Halifax — the gap is too wide. A call has to sit early or late for one side. Early morning in Tokyo is the usual compromise, since that is late afternoon or evening in Halifax.
A note on AST: it can also mean Arabia Standard Time (UTC+3). This page means Atlantic Time.
Atlantic Time (ADT) is used in Nova Scotia, New Brunswick and Puerto Rico
Other conversions
- AST to JST
- JST to UTC
- JST to GMT
- JST to EST
- JST to CST
- JST to MST
- JST to PST
- JST to AKST
- JST to HST
- JST to BST
- JST to CET
- JST to IST
- JST to CST (China)
- JST to AEST
- JST to Mexico City
- JST to BRT
- JST to ART
- JST to EET
- JST to WET
- JST to MSK
- JST to TRT
- JST to SAST
- JST to WAT
- JST to EAT
- JST to GST
- JST to PKT
- JST to ICT
- JST to WIB
- JST to SGT
- JST to HKT
- JST to KST
- JST to PHT
- JST to AWST
- JST to ACST
- JST to NZST
- All zones