IST — which one do you mean?
IST means 3 different things, and they are
hours apart. If you received a timestamp labelled IST, the sender's
location decides which of these applies — pick it below.
India Standard Time · Asia
05:45:44
Thursday, 13 August 2026
- abbreviation denotes
- +05:30
- in force right now
- IST (UTC+05:30)
- use in code
- Asia/Kolkata
- also valid
- Asia/Colombo
- next clock change
- none — fixed offset
By far the most common meaning by search volume.
Irish Standard Time · Europe
01:15:44
Thursday, 13 August 2026
- abbreviation denotes
- +01:00
- in force right now
- IST (UTC+01:00) · DST
- use in code
- Europe/Dublin
- next clock change
- 25 Oct 2026 01:00 → GMT
Ireland runs IST in summer and GMT in winter — legally the reverse framing of the UK, same clock.
Israel Standard Time · Asia
03:15:44
Thursday, 13 August 2026
- abbreviation denotes
- +02:00
- in force right now
- IDT (UTC+03:00) · DST
- use in code
- Asia/Jerusalem
- next clock change
- 25 Oct 2026 01:00 → IST
Israel switches to IDT (UTC+3) in summer.
Right now this zone is on IDT, not IST —
they are the same place at different times of year.
Use the IANA name, not the abbreviation
Python
from datetime import datetime
from zoneinfo import ZoneInfo
# right: an IANA zone carries the full history of rule changes
now = datetime.now(ZoneInfo("Asia/Kolkata"))
print(now.isoformat(), now.tzname())
# wrong: an abbreviation is not resolvable, and a hard-coded offset
# silently rots the next time the rules change
# now = datetime.now(timezone(timedelta(hours=...))) # don'tIST questions
What does IST stand for?
IST has 3 distinct meanings in active use: India Standard Time (+05:30, Asia/Kolkata); Irish Standard Time (+01:00, Europe/Dublin); Israel Standard Time (+02:00, Asia/Jerusalem). Which one applies depends entirely on who wrote the timestamp.
What time is it in IST right now?
India Standard Time: 05:45 on Thursday (IST); Irish Standard Time: 01:15 on Thursday (IST); Israel Standard Time: 03:15 on Thursday (IDT).
Which IANA timezone should I use instead of IST?
Asia/Kolkata for India Standard Time, Europe/Dublin for Irish Standard Time, Asia/Jerusalem for Israel Standard Time. Date libraries cannot resolve bare abbreviations, and an abbreviation carries no daylight-saving history, so a stored offset silently rots when a government changes the rules.