Multicultural Calendars: Every Holiday, Every Date

IWishU ships with 14 calendars. This page lists all of them, with the exact dates the app uses and - where a date moves - the reason why. No guesswork: if a date cannot be known for certain years ahead, the app says so instead of pretending otherwise.

How Calendars Work in the App

• One religious calendar per group, plus the International one. The limit is deliberate: a contact belongs to one tradition, and wishing them both Christmas and Eid would mean writing on the wrong day for one of the two. Personal calendars add on freely.
• Advance notice you choose, from 1 to 7 days before the date.
• Honest dates. Every holiday carries a reliability level, shown below and inside the app.

Fixed Same date every year, or computed by a deterministic rule.
Confirmed Moves every year, but verified against primary sources.
Estimated Cannot be certain: depends on a moon sighting or on the observer's location. The app warns you before you send.

Christian Calendars

Three separate calendars, because the traditions do not share the same dates. Orthodox Christmas falls on 7 January, and the two Easters coincide only in some years.

Catholic

Protestant

Orthodox

Jewish Calendar

The Hebrew calendar is arithmetic, not observational: dates are calculated exactly and do not depend on anyone sighting the moon. That is why they are marked as confirmed rather than estimated. The app uses the first day of each festival, not the eve at sunset.

Confirmed through 2030.

Islamic Calendar

These dates depend on the sighting of the moon, announced only days in advance and different from country to country. No source can give them as certain years ahead, so IWishU declares a single reference - the Umm al-Qura calendar of Saudi Arabia and the Gulf - rather than mixing sources, and tells you the date is provisional.

Estimated - expect a difference of up to one day depending on where the person you are writing to lives.

East Asian Calendars

Chinese

Determined astronomically by the new moon and published decades in advance, so the dates are reliable well ahead of time.

Confirmed through 2030. Zodiac years: Horse, Goat, Monkey, Rooster, Dog.

Japanese

Buddhist Calendars

Three distinct traditions, each celebrating the Buddha on a different day - which is precisely why they are separate calendars rather than one.

Hindu Calendar

Sikh Calendars

Two calendars, because the Sikh community itself follows two. The difference is not cosmetic: it changes the date of one of the three festivals.

Guru Gobind Singh's birthday in the SGPC calendar is marked Estimated: the date is reported inconsistently even among official Sikh sources.

International Calendar

The secular calendar, which adds freely on top of any religious one. It exists because the most universal occasion of all - New Year - belonged to no calendar at all.

How Far Ahead the Dates Go

Lunar dates are compiled by hand from primary sources, and sources publish with different horizons. When a calendar runs out of data, the app tells you inside the group card instead of quietly going silent - which is the failure that would otherwise look like the app simply not working.