Gregorian Calendar
The real-world calendar, leap years and all, as a neutral default.
The everyday calendar of the modern world: twelve months over a 365-day year and a seven-day week. Every fourth year is a leap year, in which February gains a twenty-ninth day — except for years divisible by 100, unless they are also divisible by 400. So 2024 and 2000 run 366 days while 1900 runs 365.
Months in 1 AD
365 days / epoch year 1 AD
- January (31 days)
- February (28 days)
- March (31 days)
- April (30 days)
- May (31 days)
- June (30 days)
- July (31 days)
- August (31 days)
- September (30 days)
- October (31 days)
- November (30 days)
- December (31 days)
- Leap Day — 1 extra day on February every 4 years, except every 100, unless every 400.
Week
- Sunday
- Monday
- Tuesday
- Wednesday
- Thursday
- Friday
- Saturday
Moons
- The Moon (30-day cycle)