How many time zones exist?

There is a total of 400+ registered time zones, as accounted on a per country/naming basis. Only about 38 of those are unique.

Why do we have repeat time zones?

You may have noticed the existence of multiple time zones that appear to have the same offset and abbreviation. For example America/Belize, America/Guatemala, and America/Managua, America/Mexico_City, America/Costa_Rica, America/El_Salvador, America/Regina, America/Tegucigalpa all using Central Standard Time (CST). This can be attributed to several practical and administrative reasons:

• Regional Identity and Autonomy

  Each country prefers to have a time zone identifier that reflects its national identity. Even though Belize, Guatemala, and Nicaragua share the same CST time, they use distinct identifiers to emphasize their sovereignty and unique national context.

• Administrative and Technical Precision

  In computing and international systems, having distinct identifiers for time zones helps avoid ambiguity. For instance, "America/Belize" clearly indicates the time zone specific to Belize, which can be important for software systems, scheduling, and global coordination.

• Daylight Saving Time (DST)

  Although countries may share the same base time zone, their observance of DST can differ. Separate identifiers allow for accurate representation of these variations. For example, one country might observe DST while another does not.

• Historical and Political Context

  Historical reasons also play a role. Time zones might have been established independently during different periods, reflecting historical political boundaries and agreements. Political boundaries often influence time zone designations. Even if countries are geographically close, distinct time zone identifiers respect their political and administrative boundaries.

• Regional Administration

  For administrative purposes, it is often more practical to have a unique time zone designation for each country or region. This helps local governments, businesses, and citizens to coordinate activities more efficiently.

• Standardization Bodies

  International bodies like the International Telecommunication Union (ITU) and the Internet Assigned Numbers Authority (IANA) create and maintain time zone databases that require unique identifiers for clarity and precision. The IANA Time Zone Database, for instance, includes specific entries for different regions to facilitate accurate global timekeeping.

  
  
  

Why do we have more than 24 unique time zones?

Even so, there should only be 24 unique time zones. The Earth is a sphere (not a perfect one according to NASA), with 360 degrees in longitude. As it rotates on its axis, it creates night and day periods, based on the sun's exposure. That rotation process takes 24 hours, so that’s the length of a day.

Therefore, that would make an even 24 time zones,  each 1 hour apart. However, we have separated the earth into countries, each with its own culture and politics, which is were things get complicated (read more here).

A list of all time zones, the associated country, abbreviation and raw offset -not accounting for DTS-

Avoid the time zone confusion by using our free and visual time zone convertor here.

Written by:

Sofia Kyriazidi

MeetMomentum
Founder

Sofia Kyriazidi