THE GREGORIAN CALENDAR

Months:

1. January - 31 days
2. February - 28 days
3. March - 31 days
4. April - 30 days
5. May - 31 days
6. June - 30 days
7. July - 31 days
8. August - 31 days
9. September - 30 days
10. October - 31 days
11. November - 30 days
12. December - 31 days

Gregory merely modified the Julian calendar, refining the calculation the leap day that by 1582 had resulted in 10 extra days. So, in October 1582, the 4^th was followed by the 15^th.

In a leap-year, February is given a 29^th day. A leap-year is any year divisible 4, as designed by Julius Caesar. However, Gregory modified this, in that all double-zero years (divisible by four) would only be leap-years if also divisible by 400.

Within this, it uses weeks of 7 named days, but these do not directly correspond to specific dates, so vary month to month and year to year. These are of Western tradition, but are probably not directly linked to the Gregorian calendar. I've provided the English names because this document is in English, but many other languages have similar or drastically different names for a seven-day-week:

Days:

1. Sunday
2. Monday
3. Tuesday
4. Wednesday
5. Thursday
6. Friday
7. Saturday

I've cross-referenced this calendar in my perpetual calendar with several other solar calendars.