Calendar Calculations

Methods and patterns for determining dates, weekdays, and year types.

Articles with this tag: 3 Updated: August 23, 2026

Articles with this tag

Common year starting on Saturday — calendar characteristics and examples Common year starting on Saturday Details of a common (365-day) year whose January 1 falls on Saturday: weekday layout, month starts, holiday dates, Friday the 13th pattern, ISO-week effects, Gregorian/Julian notes…

Hebrew calendar (Jewish calendar) Hebrew calendar A lunisolar calendar used in Judaism to determine religious observances, festivals, life-cycle events and liturgical cycles; it combines lunar months with periodic leap months to s…

July — seventh month of the Gregorian calendar

July — seventh month of the Gregorian calendar July July is the seventh month of the Gregorian calendar, has 31 days, lies between June and August, and is named for Julius Caesar. It marks midsummer in the Northern Hemisphere and in…