This table is a source of information about the 25 individual time zones, each being a 15 degree segment of the earth's 360 degrees. (Actually zones M and Y cover only 7 and 1/2 degrees each, totaling 15 degrees. That is the reason for the 25 zones instead of 24. There is no zone J.) The first column shows the specific longitudinal (meridional) degree range from the prime (Greenwich) meridian (See GMT, UTC, atomic time or Zulu time.) The second column denotes the time deviation in hours from the ZULU time zone. The third column shows the alpha designation for the time zone. The prime meridian zone is designated Z for Zulu. You may wish to see Zulu Time (UTC) in relationship to other time zones, check out Time Zone Converter. To check the atomic time at the U.S. Naval Observatory, click here.