Time zone map
The boundaries wander because they follow borders rather than meridians — which is exactly what makes a map more useful than a list.
The short answer
A time zone map shows which offset applies where. In a geometric world the bands would be 15° wide and the boundaries straight north–south lines.
They are not. Boundaries follow national and regional borders, jog around cities, and in places swallow several hours of longitude in a single zone.
Why the boundaries wander
Every deviation from a straight line is a political decision.
China uses one zone for a country spanning about five hours of solar time — the single largest deviation on the map.
Spain sits at roughly the longitude of Britain but uses Central European Time, a decision from the 1940s that was never reversed. Spanish solar noon is therefore unusually late, which is part of why the national schedule runs late.
Argentina uses UTC−3 across a country whose western edge would justify −4.
The US–Canada boundary jogs repeatedly to keep towns, counties and rail hubs on a single clock.
Kiribati produced the biggest kink of all when it moved its eastern islands across the date line in 1995, creating a large eastward bulge at UTC+14.
What a map shows that a list does not
Adjacency. Who is next to whom, and where a short distance crosses a large jump. The Samoa / American Samoa pair — an hour apart on the clock and a full day apart on the calendar — only makes sense visually.
The date line's shape, which is impossible to convey in a table.
Relative width. The visual disproportion between Russia's eleven zones and China's one carries the point immediately.
Time zone map versus day/night map
Different things, often confused.
| Shows | Changes | |
|---|---|---|
| Time zone map | Which offset applies where | Rarely — when laws change |
| Day/night map | Where sunlight currently is | Continuously |
A time zone map is a reference. A day/night map is a live instrument — the terminator sweeps west continuously, and its shape changes through the year with the earth's tilt.
For "what time is it there" you want the first. For "are they awake" you want the second, and the second is usually the real question.
Reading offsets off a map
Most maps label bands by UTC offset. Two cautions:
Daylight saving is rarely shown. A map labelled UTC−5 for the US east coast is correct in winter and an hour out for the eight months of EDT.
Half-hour zones are easy to miss. India, Nepal, Iran, Myanmar and parts of Australia sit on fractional offsets, and small labels on a world map tend to round them.
Related: World time zone map · US time zone map
Timezone: World Clock Widget
A world clock, converter and live day/night map for iPhone — 325 cities, offline, no account.
Figures on this page are computed from the IANA time zone database. Last generated 2026-08-18.