TIME ZONES Earth rotates around axis once every 24hrs. Therefore there are 24 time zones around the earth with 1 hr difference between them. Developed by Sir Sanford Fleming, Canada’s most experienced civil engineer. Universal Time Zone Located in Greenwich England – is the prime or zero meridian Line is the center of a time zone that extends 7.5 on either side and is the standard time all other zones are compared to. International Date Line 180 line of longitude through N-S poles cross date moving west you add a day cross date moving east subtract/lose a day Daylight Saving Time 2nd Sunday of March (spring ahead) 1st Sunday of November (fall behind) (from 19887 to 2006, DST was from the first Sunday of April to the last Sunday in October).