Festival Forecaster

The "Moving Target" of Islamic Dates

Calculating the Islamic calendar (Hijri) against the Gregorian calendar is complex. The lunar year is approximately 11 days shorter than the solar year. This means every Islamic holiday "travels" backwards through the seasons, completing a full cycle every 33 years.

Why does this matter for HR?

It prevents you from having a static "Busy Policy". For the last decade, Ramadan has been in the Summer (long days, high heat, fatigue risk). Ideally, your policy focused on energy management.

As we move into the Winter cycle (2026 onwards), the fasting day becomes much shorter (easier), but it clashes heavily with the standard 9-5 workday.

• Summer Ramadan: Fasting 18 hours. Fatigue is the issue. Leaving at 5pm is fine as Iftar is at 9pm.
• Winter Ramadan: Fasting 10 hours. Fatigue is low. But Iftar is at 4pm. Staff need to leave during the working day.

The "Moon Sighting" Variance

You cannot automate Islamic leave with 100% accuracy because the dates depend on the physical sighting of the new moon. This often leads to the chaos of "The 24-Hour Notice".

• The Global vs Local Debate: Some UK Muslims follow Saudi Arabia's moon sighting. Others wait for a sighting in the UK/Morocco. This means your staff might celebrate Eid on different days.
• The Fix: Do not just book "Eid Day". Book an "Eid Provisional Window". Approve 2 days of leave, with the agreement that the unused day is cancelled or taken as extra.

Critical Dates Explained

Ramadan (The Month of Fasting)

Lasts 29 or 30 days. No food or water from dawn to sunset. High Impact Impact: The first 3 days (caffeine withdrawal) and the last 10 days.

Laylatul Qadr (The Night of Power)

Occurs in the last 10 odd nights of Ramadan. Muslims stay up all night praying. This is the peak danger zone for sleep deprivation. Avoid 9am meetings during the last 10 days of Ramadan.

Eid al-Fitr (Festival of Breaking the Fast)

The "Big Party" at the end of Ramadan. Comparatively, this is like Christmas Day. Expect 100% absence request rate.

Eid al-Adha (Festival of Sacrifice)

Occurs roughly 2 months and 10 days after Eid al-Fitr. It coincides with the Hajj pilgrimage. It usually lasts 3 days, but most UK staff take 1-2 days off.