How do timezones work?

Question

Okay I have a question and it might be very stupid but I can’t figure it out. So you know timezones, they start at GMT, and when you go to the right you add one hour and when you go to the left you take away one hour. BUT as these timezones go around the Earth, they meet on the other side. So there’s 24 timezones(?), and they start at 0 a GMT, and they would go 12 hours to the right (so 12 hours ahead of GMT) and -12 hours to the left (12 hours behind GMT) (I know that adds up to 25 timezones but it’s not important lol), so that means that the 12 hours ahead timezone and the 12 hours behind timezone is right next to each other?? So if you go from one of those two timezones to the other the day just goes by by 12 hours? Please explain lol

Answer 1

Thank you - it ALL makes sense now. The IDL was the thing that made it make more sense. Had no idea that was a thing

Answer 2

There are 24 MAIN Times Zone and some locations have decided to split them. That is why one answer said there were more than 24.

Times Zones are determined by Lines of Longitude. There is 360 Degrees in a Circle and there are 24 Time Zones

360 divided by 24 = 15. Each Time Zone is 15 Degrees of Longitude Wide.

GMT time Zone is Centered on Longitude Zero Degrees which passes through the Royal Observatory at Greenwich England. Longitude and Time are Measured East and West from Greenwich to the International Date line at 180 Degrees longitude. When you cross the International Date Line you change Days. That is why the International Date line does not pass through any Countries and is in the middle of the Pacific Ocean. It does not follow 180 exactly but skips around a bit to avoid passing through one of the South Sea Island countries.

I Live in Brisbane Australia Time Zone GMT+10 Meaning I am 10 Hours Ahead of London and 20 Hours Ahead of Hawaii which is in Time Zone GMT-10

When looking at the difference in Time Zones you do not cross the International Date Line. Like when I stated the Difference Between Brisbane Australia and Hawaii. the short distance between the two is across the Date Line but I can't do that to figure the time difference.

I hope this is clear.

Answer 3

12 hours behind, they meet but with a difference of 1 day. That longitude is named 'International date line' (IDL). On the east (right as per you language) is 1 day behind that of west (left). As per the convention if you cross the line (on aircraft or ship) you are required to change the day/date. This can be called IDL correction.

Answer 4

No, there are NOT 24 time zones. There is something like 38 time zones. The new "day" begins at international dateline halfway around the world from the Greenwich Observatory at 0 degrees longitude, but the international dateline is NOT a straight line., Some time zones . like India's and Pakistan's' are off set a hlf your. Others are offset by 45 minutes from the hour. Australia's time zones seem entirely crazy. New South Wales can be 2 and hours earlier than Sydney Australia's time zone..





There are 39 time zones, NOT 24.The reasons time zones exist are economical and

cultural, and sometimes political. ALL of China is ONE time zone, but China is 4 time zones wide..Russia has 8 time zones.. The Reason that Arizona does not observe daylight savings time.The Atlantic time zone is offset by half an hour. The reason Arizona does not observe daylight saving time is, except on the Native American reservations, which like to be in the same time zone as the rest of their tribes in the surrounding states (cultural) is Arizona is so far west in the timezone and San Diego and Phoenix are economic hubs tied together and are in the SAME time zone , Pacific daylight time, for more than half the year..



I lived in Arizona for year. The Arizonans LIKE being in the same time zone as the west coast.. It kind of made sense to me when i lived there. but once i took economic geography, it more than 20 years ago, it makes COMPLETE sense..



There are 39 time zones NOT 24..



"...How Many Time Zones Are There?



If each time zone were 1 hour apart, there would be 24 in the world. But several time zones have only 30 and 45 minutes offsets, making the total number worldwide much higher.



Interactive Timezone Map from timeanddate.com

Our Time Zone Map shows all current time zones.



©timeanddate.com



More Than 24 Time Zones

If each time zone were 1 hour apart, there would be 24 in the world.



However, the International Date Line (IDL) creates 3 more. Also, several time zones are only 30 or 45 minutes apart, increasing the total number of standard time zones even further.



Daylight Saving Time Zones

During Daylight Saving Time (DST) the time zone name and time changes. The words “daylight” or “summer” are then usually included in the name, and the local time is usually set forward 1 hour.



For example, California uses Pacific Daylight Time (PDT) during the DST period with a UTC offset of UTC-7, but Pacific Standard Time (PST) with an offset of UTC-8 during the rest of the year.



Not the Same as Local Time

The term time zone is often confused with local time. For instance, during DST, it is common to say “California and Arizona are now in the same time zone.” However, the correct thing to say would be: “California and Arizona now have the same local time.”



The reason it may be confusing is that California's local time during DST is UTC-7, but the standard time in California is UTC-8. However, Arizona's local time is always UTC-7, because there's no DST in Arizona, and they remain on standard time all year.



Time Zone Borders Vary

Theoretically, each 1-hour time zone is 15 degrees wide, indicating a 1-hour difference in mean solar time. This can be seen as the white and gray stripes on our Time Zone Map and in the image above.



The actual borders on a time zone map have been drawn to correspond with both internal and international borders, and rarely match up exactly with the 15-degree time zone borders.



Some geographically large (wide) countries, like India and China, use only 1 time zone, while it would have been natural to expect several, like in the US or Australia.



Defined by UTC Offset

Every place on Earth is measured in terms of its distance east or west of the prime meridian (0°longitude) in Greenwich, London, United Kingdom. This is also the reference point for Coordinated Universal Time (UTC) with 1 hour per 15 degrees longitude.



You have to divide the longitude, in degrees, by 15 to find the appropriate time zone, in hours. For example:



At 150 degrees west (or 150° W) longitude, the time should be 150 degrees divided by 15 degrees = 10 hours behind UTC, or UTC-10.

At 75 degrees east (or 75° E) longitude, the time would be 75 degrees divided by 15 degrees = 5 hours ahead of UTC, or UTC+5.

Below are all the different local times currently in use worldwide.



Currently 39 Different Local Times in Use..."



https://www.timeanddate.com/time/current-number-time-zones.html

Answer 5

It is based on the revolution of the earth in respect to the sun. 24 time zones because a day is divided into 24 hours.

Answer 6

You are correct in that T and T+24 (or T-12 and T+12) touch each other. When you cross that line, the International Date Line, the time changes by 24 hours, either forward or backwards depending on which way you cross it. So just like you gain a couple hours when you travel far enough east or west, if you travel far enough you'll cross the IDL and lose not 2 or 3, or 12, but 24 hours. If I'm correct, there's no populated land under it.