World Time date issue

[IAmShawky]

I got S6 edge phone here in Egypt and i notice in world time when i choose some countries like Greece or UAE which r similar in same day date but different in hour i notice that the date of other countries is shifted for example if date nw in egypt 9th September when i check the date in Greece which is supposed to be similar it gives me 8th September if here is 10 there is 9 and so on what steps should i make to solve this issue