Pokémon Sun and Moon/Version differences

There are a number of differences between Pokemon Sun and Moon.

Time of day
Sun and Moon are set 12 hours apart, so Sun follows the system clock, whereas Moon in-game time is transposed 12 hours from the system clock. For instance, if it is 10AM on the system time, the in-game time in Sun will be 10AM, but in Moon it is 10PM.

Totem of Melemele Island
Sun has Gumshoos: Moon has Alolan Rattata.

Version-exclusive Pokemon
Sun: Passimian, Lycanroc (Midday Form), UB-02 Expansion, Solgaleo. Moon: Oranguru, Lycanroc (Midnight Form), UB-02 Beauty, Lunala.