Yes, I usually find it easier to memorize things starting from base concepts. (I don't see the Sun moving right to left, but the Earth turning counter clockwise

Yes, I usually find it easier to memorize things starting from base concepts. (I don't see the Sun moving right to left, but the Earth turning counter clockwise when seen from the North pole). There's no way to memorize the X hours ahead/behind meaningfully, since the sign of numerical timezone offset may be flipped, depending on the operation AND on the system used. Eg. systems designed in the USA often use an opposite offset, (so they have negative offsets to Europe). The Greenwich Observatory defines positive offsets East and negative West: http://wwp.greenwichmeantime.com/info/timezone.htm http://wwp.greenwichmeantime.com/info/timezone.htm So GMT+8 is in China. But for POSIX, GMT+8 is the USA, like in Common Lisp, where: "Time zone values increase with motion to the west, so Massachusetts, U.S.A. is in time zone 5, California, U.S.A. is time zone 8, and Moscow, Russia is time zone -3." To be noted that both those systems were designed in the USA.