Local Mean Time changes by a day when crossing 180 E/W
reason - depends on the position of the sun w.r.t the meridian.
Standard Time changes by a day when crossing International Date Line
reason - country decides its standard time so that east and west part of that country doesn't have much of a difference in time and in cases like Fiji, New Zealand etc. some part is to east some part is to the west of 180 and the date line is adjusted accordingly.
