Are all time zones exactly on the hour?
I know in the US, all the time zones are exactly one hour apart, but are all of the time zones around the world like that?
The world of 40 zones
This globe of ours is broken up into 40 different time zones, which should be a bit of a giveaway, as at last count, there were only 24 hours in a day.
To make things more complex, there are 25 separate nautical time zones, but for the sake of simplicity, let’s just examine the land-based ones.
Universal time
Each time zone in the world is expressed as an offset of Coordinated Universal Time, or UTC — which was formerly known as Greenwich Mean Time, or GMT. UTC is the primary time standard by which the entire world regulates clocks and time — all “official” time in the world is based on UTC.
So, if you live on the east coast of the US, your time zone is listed as UTC-05:00 — assuming Daylight Saving Time is not in effect, which is a whole ‘nother can of worms that I won’t open here.
As such, this means that outside of DST, the time in New York is five hours behind UTC. So, if it’s 10pm UTC (which technically would be expressed as 2000 UTC), it would be 5pm in New York (10-5=5). Simple enough.
On the other hand, if you’re in Japan, your time zone is UTC+09:00 — meaning if it’s 10pm UTC, it’s already 7am the next day in Japan.
The non-hourly time zones
Now, if this whole mess isn’t confusing enough, there are several time zones that, for the sake of accuracy, politics, and a host of other reasons, do not fall exactly on the hour. Here’s the list, with some example locations for reference:
UTC-09:30 Marquesas Islands
UTC-04:30 Venezuela
UTC-03:30 Newfoundland
UTC+03:30 Iran
UTC+04:30 Afghanistan
UTC+05:30 India and Sri Lanka
UTC+05:45 Nepal
UTC+06:30 Cocos Islands and Myanmar
UTC+09:30 Australia’s Northern Territory
UTC+10:30 Lord Howe Island
UTC+11:30 Norfolk Island
Additionally, there are three time zones that have an offset of over 12 hours ahead of UTC (while still lying west of the International Date Line, hence the over 12 hours offset), though only one does not exactly fall on the hour. They are:
UTC+12:45 Chatham Islands
UTC+13:00 Tonga
UTC+14:00 Kiribati (Line Islands)
For a more complete list of time zones and corresponding countries, including when (and if) DST takes effect for them, check out this publication from the International Telecommunication Union (ITU).
