In the answer to question no. 12660 we stated that if the Muslim is in a Muslim country that relies on sighting of the moon to mark the beginning and end of the month, then he must follow that country, and it is not permissible for him to differ from it in starting and ending the fast.
The Prophet (peace and blessings of Allaah be upon him) said: “The fast is the day when you fast, breaking the fast is the day when you break the fast, and sacrifice is the day when you offer the sacrifice.” Narrated by Abu Dawood (2324) and al-Tirmidhi (697); classed as saheeh by al-Albaani in Saheeh al-Tirmidhi.
The imams differed with regard to the question of whether, if the moon is sighted in one place, all the Muslims are obliged to fast, or are only the nearby countries obliged to fast and not the distant countries, or are those whose sighting coincides with that sighting obliged to fast, and not those whose sighting did not coincide with it? There are several opinions.
The Muslim should follow the scholars of his own country in whichever of these views they believe to be more correct, based on the evidence that they have available, and he should not start or end the fast on his own.
We have quoted the statement of the Council of Senior Scholars on this issue in the answer to question no. 50487, in which they said:
… the members of the Council of Senior Scholars think that matters should be left as they are and that this subject should not be stirred up. Each Islamic state should have the right to choose whichever opinion it wishes, based on the suggestions of its own scholars, because each view has its evidence and proofs.
Please read this statement in full, because it is important.
Based on this, you should follow your country which relies on the sighting of the moon to establish the beginning and end of the month and the beginning and end of the fast. If you do that, you will have done well and you are not required to make up the fast.
And Allaah knows best.