how many time zones are in the world?
LOADING19:25:43Tokyo, JapanMondayApril 9, 2018Â© 24TimeZones.com By convention, the 24 main time zones on Earth compute their local time as an offset from UTC, each time zone boundary being ostensibly 15 degrees east or west of the preceding one. The reference point for UTC is the Greenwich Meridian (the Prime Meridian), which has a longitude of 0Â°.