how many time zones are they?

Answer 1

There are 25 integer World Time Zones from -12 through 0 (GMT) to +12. Each one is 15° of Longitude as measured East and West from the Prime Meridian of the World at Greenwich, England. Some countries have adopted non-standard time zones, usually 30 minutes offset which have a * designation.

Answer 2

Indeed, everyone simply blurting out "24" because there are 24 hours in a day have no idea what they are talking about.

The real answer is that it's not an easy question to answer. There are no less than 37 "standard" time zones, for many many places have zones on the 1/2 hour. Beyond that, the US military has its own set of time zones that it uses for military purposes. Add to that other countries around the world which use yet more time zone systems.

Answer 3

24... no more, no less

Standard time zones can be defined by geometrically subdividing the Earth's spheroid into 24 lunes (wedge-shaped sections), bordered by meridians each 15° of longitude apart. The local time in neighbouring zones is then exactly one hour different. However, political and geographical practicalities can result in irregularly-shaped zones that follow political boundaries.

There are variations of the definitions of time zone which generally fall into two meanings: a time zone can represent a region where the local time is some fixed offset from a global reference (usually UTC... eg province of Newfoundland in Canada. which has a time zone a 1/2 hr difference from the next time zone), or a time zone can represent a region throughout which the local time is always consistent even though the offset may fluctuate seasonally.

Answer 4

This depends if you're looking at it from a physical science point of view or a political one.

Time zones are centered on lines of longitude 0, 15, 30....and extend 7 1/2 degrees in each direction, giving us 24 time zones. However these lines often cut through countries or states and are not convenient..so local governments can and do change them to suit their needs, giving us a more complex system. Then if you want to figure in who does and doesn't use daylight savings time it's even more so...

Answer 5

It depends on what you mean by "time zone".

In the contiguous 48 states, there are four time zones, right? Well, what about (almost all of) Arizona, which doesn't observe DST? Do you call that part of the Pacific time zone in the summer, and part of the Mountain zone in the winter? Or do you call it a fifth time zone?

Now, compare Chile to Canada's New Brunswick province. They're both in the same colored stripe on the map, the one where standard time is four hours earlier than Greenwich. They both observe DST, which means they set their clocks ahead an hour in the summer. The trouble is, Chile is in the southern hemisphere, where the summer is December to March. When New Brunswick's clocks are ahead, Chile's are normal, and vice versa, so for most of they year they have different times. Are they in the same time zone?

The simplest way to answer your question is to forget about DST, and just ask how many different standard times there are. The answer is at least 38: every whole number of hours from Greenwich minus 12 to Greenwich plus 14 (that one is in Kiribati), plus nine half-hour zones and two quarter-hour zones (Nepal, and New Zealand's Chatham Island).

That's either more than you need to know (if you're just curious), or less than you need to know (if you're programming a computer to convert time zones, for example). If you need to know more, one place to start is shown below.

Answer 6

24

Answer 7

It varies depending on how deep you want the answer.

25 hourly zones or 37 to include the ones that feature the half hourly zones are all correct, as per the prior answers.

Anyone who said 24 is making the common ignorant mistake based on their being 24 hours per day.

Answer 8

I think there's about 31 - the obvious 24 hourly ones and some other places like India that have a 5 1/2 difference from GMT.

Check out http://www.thetimedifference.com/

PS Ignore those that say 24 - there's other countries like Afganistan and norther Australia that have half hour differences.

Answer 9

there are 24 different time zones in the world.

Answer 10

24. There is one for every hour of the day.

Think of the timezones laid out flat across the world - with London at 12noon. All countries fit into their hour slot, although some are spot in the middle of the hour so get half hour. There are still only 24 zones.

India is set to a half hour - to put the whole country in the same zone.
Nepal is at 17.45 when London is at 12 noon