In Hadith,it is said that Allah comes to the nearest sky from earth at last night(last 1/3rd of night).But it is seen that in various regions of world that's time come at various time.It may also seen that this particular time(last 1/3rd night)exists all the 24hrs of earths moving even on a single land of earths.So how what way should we consider to remove the condradiction?
Allah's Messenger (ﷺ) (p.b.u.h) said, "Our Lord, the Blessed, the Superior, comes every night down on the nearest Heaven to us when the last third of the night remains, saying: "Is there anyone to invoke Me, so that I may respond to invocation? Is there anyone to ask Me, so that I may grant him his request? Is there anyone seeking My forgiveness, so that I may forgive him?"
Moral of this hadith be that people should especially do du'a when their (local) time is last third of the night as Allah will bless this time (for them). It can be different for different locations. It can be that it happens at one instant for the people of one hemisphere and happen again for people of another hemisphere. Allah has power to do accomplish all things.
As for Allah descending to the lowest heaven this is from the Mutashabihat. Humans can not understand it, only Allah knows what it really means. People should refrain from interpreting it and not take it literally nor metaphorically. The meaning and nature of descent is beyond human understanding. If you take it literally then it implies that god has a body and is encompassed by space and time and if you give your own interpretation then you distort the words or make a claim without proof.