Fasting During the Long Days of Summer
Referring this question to Dr. Hatem Al–Haj, he said:
In places where there is no day or night, the Muslims will fast according to the times of the closest city that has day and night.
For those who find it incapacitated by fasting during one of those days with long hours, and it is truly so (Allah is the best observer), they are allowed to break their fast and make that day up at some other time of the year, for Allah doesn’t burden souls beyond their capacity.
Allah said what means: “Observing Saum (fasts)] for a fixed number of days, but if any of you is ill or on a journey, the same number (should be made up) from other days. And as for those who can fast with difficulty, (e.g. an old man), they have (a choice either to fast or) to feed a Miskin (poor person) (for every day). But whoever does good of his own accord, it is better for him. And that you fast is better for you if only you know.” [2:184]