Ramadan this year is expected to begin on May 15, according to the Sharjah Centre for Space and Astronomy.
It means the first day of Eid Al Fitr is expected to fall on June 15, reported the Government news agency Wam.
The exact dates of the holy month will be confirmed by the moon sighting committee.
The Sharjah Space and Astronomy Centre said the length of the fast is likely to be 13 hours and 25 minutes at the beginning of Ramadan, increasing to 13 hours and 42 minutes by the end of the holy month.
This will be the first time in 18 years that the fasting period will be longer at the end than in the beginning, because Ramadan 2018 will happen before the summer solstice , or the longest day.
In 2000, Ramadan fell between November 27 and December 27, and included the winter solstice, or the shortest day.
Temperatures in June will range from 26°C to 41°C, the centre said, with spikes of 3°C to 5°C possible during heat waves.
The Ministry of Education has yet to announce the new Ramadan hours for schools. Last year, the daily public school hours were reduced to five, with classes for girls running from 8am until 1.15pm and for boys from 9am until 2.15pm. A circular is usually issued to schools from the MoE a few days before the start of the holy Month to confirm any changes.
As they did last year, this year thousands of pupils will again have to sit their end-of-year examinations while they are fasting. Pupils in Grade 12 attending public or MoE-curriculum private schools will sit for their national Grade 12 examinations during the first two weeks of Ramadan, from May 14 to May 24.
For American and British curriculum pupils, exams will generally fall around the last week of May to the first week of June, with each school varying slightly. GCSE, AS and A-levels subject exams will be administered from May 7 to June 29.
The academic year will end July 5 for pupils and July 12 for teachers. The MoE has yet to release the academic calendar for the next academic year.