WST time zone — 2 different meanings
WST means 2 different things: Western Standard Time at UTC+08:00 and West Samoa Time at UTC+13:00. The extremes are 5 hours apart and nothing in the three letters says which was meant. Put a timestamp into the panel below and it is read as every meaning at once, in your own clock, so you can see what you would be risking by guessing.
A time written 15:00 WST on is, in your time:
2 meanings, 5 hours apart. Guessing wrong moves the appointment by up to 5 hours.
2026-07-27T15:00:00+08:00 Shown in UTC until your clock is read. Send the line above instead of the letters — it cannot be read two ways.
The 2 meanings of WST
- UTC+08:00 Western Standard Time Western Australia. Australia/Perth
- UTC+13:00 West Samoa Time Samoa, which is a day ahead of American Samoa next door. Pacific/Apia
Why one code means 2 things
Nobody ever standardised these letters. They grew up regionally, in railway timetables and broadcast schedules, and by the time software needed to parse them the same three characters were already in use on opposite sides of the planet. There is no registry that can settle it, because there is no registry. WST is Western Standard Time at UTC+08:00 and West Samoa Time at UTC+13:00 — and a machine reading the string has no way to choose.
The practical consequence is 5 hours wide. A meeting written as 15:00 WST lands anywhere in a 5-hour window depending on which meaning the sender had in mind, and the reader usually has exactly one clue: where the sender is. That clue is often wrong, because the sender may be quoting a system that stamped the abbreviation from a server's own locale rather than from theirs.
Write this instead
If you are the one sending the time, the fix is small and permanent. Use the IANA zone name — Australia/Perth, Pacific/Apia — or an ISO 8601 timestamp with a numeric offset, which looks like 2026-03-14T15:00:00+08:00. Both are unambiguous, both survive a daylight-saving change, and both are what calendar software and databases actually store underneath whatever they show you.
The zone name is the stronger of the two, because it carries the rules and not just the number. An offset is true for one instant; a zone is true for the year. If you write UTC+08:00 into a recurring meeting, half of that series will be an hour out after the clocks change.
How to use this
- Type the date and time exactly as it was written to you, then read the row for the meaning you believe was intended.
- Switch to "I mean my own time" to go the other way: enter a time on your clock and see what it should be called.
- Copy the line at the bottom into your reply — an ISO timestamp with a numeric offset cannot be misread.
Worth knowing: Nothing on this page can tell you which WST the sender meant. Only they can. What it can tell you is how much is at stake in the guess: 5 hours.
FAQ
What does WST stand for?
More than one thing: Western Standard Time at UTC+08:00 and West Samoa Time at UTC+13:00. That is not a quirk of this page — the letter codes were never standardised, so several regions ended up using the same three letters for offsets 5 hours apart.
What is WST in UTC?
Western Standard Time is UTC+08:00; West Samoa Time is UTC+13:00.
Should I write WST in a calendar invite?
No. Write the IANA zone name instead — Australia/Perth, Pacific/Apia — or an ISO 8601 timestamp with a numeric offset. Calendar software resolves zone names correctly across daylight-saving changes, and a numeric offset cannot be read two ways. Three letters can.