Reliable astronomical data from HM Nautical Almanac Office and Crescentwatch.org indicate that in South America it may be possible to see the new crescent moon as early as Thursday evening, 16 July 2015.
On Friday evening, 17th July a naked-eye (unaided) sighting of the new crescent moon will be highly probable in most regions, including the Americas, Africa, Southern Europe and Australia, and in remaining regions on Saturday night, 18th July.
Hence, Eid al Fitr could be as early as Friday, 17th July in South America, will likely be on Saturday, 18th July in most regions of the world, while in the United Kingdom, Northern Europe and much of Asia, Eid al Fitr will be on Sunday, 19th July.
Whichever day you are celebrating Eid al Fitr, the Association of British Muslims would like to wish you a most blessed and joyful Eid!
Paul Salahuddin Armstrong, Co-Director, the Association of British Muslims.