Every date

Public holidays in the US and 24 other countries; religious holy days across Christianity (Western and Orthodox), Judaism, Islam, Hinduism, Buddhism, Sikhism, Jainism, the Baha’i Faith, Zoroastrianism and pagan traditions; moon phases, eclipses, solstices and meteor showers; sports season openers, finals and majors; Minnesota hunting and fishing openers; elections and summits; Fed meetings and big-tech earnings; awards and festivals; UN days and heritage months; and round-number anniversaries and birthdays.

Anything that follows a rule is computed exactly: the sky with Astronomy Engine, Easter by the computus, Jewish dates with Hebcal, Islamic dates from the Umm al-Qura calendar, Hindu and Sikh festivals from the lunisolar calendar, US observances from statute. Everything else comes from the organizer or a checked public source, and every event links to its source.

Islamic months start with the sighting of the new moon, so local dates can differ by a day from the Umm al-Qura calendar used here. Hindu festivals follow regional almanacs. Those dates are marked tentative.

Yes. Every category and subcategory has an iCalendar feed on the Feeds page, and any filter can become a feed (for example /ics?cat=sports.nfl,sky). Every event page has an Add to calendar menu.

Every week. Computed calendars extend automatically, schedules are re-read from their sources, and every moved or cancelled date is kept on the Changes page.