Look at the graphic above. You see that? That’s a visual representation of the time zone differences between NYC, London, and Sydney in a span of 3 weeks which happens twice every year during the switchover from and to Daylight Saving Time.
As C.G.P. Grey explains so eloquently in the video below, DST is sort of a mess. And if you live in Arizona near or in an Indian reservation…well, you better brush up on your timezones because it’s an even bigger mess in that state.