Friday the 13th in the context of "Common year starting on Friday"

A common year starting on Saturday is any non-leap year (i.e. a year with 365 days) that begins on Saturday, 1 January, and ends on Saturday, 31 December. Its dominical letter hence is B. The most recent year of such kind was 2022, and the next one will be 2033 in the Gregorian calendar or, likewise, 2023 and 2034 in the obsolete Julian calendar. See below for more.

This is the only common year with three occurrences of Sunday the 13th: those three in this common year occur in February, March, and November. Leap years starting on Tuesday share this characteristic, for the months January, April and July. Any common year that starts on Saturday has only one Friday the 13th: the only one in this common year occurs in May. Leap years starting on Friday share this characteristic.

A leap year starting on Thursday is any year with 366 days (i.e. it includes 29 February) that begins on Thursday 1 January, and ends on Friday 31 December. Its dominical letters hence are DC. The most recent year of such kind was 2004, and the next one will be 2032 in the Gregorian calendar or, likewise, 2016 and 2044 in the obsolete Julian calendar.

This is the only leap year with three occurrences of Tuesday the 13th: those three in this leap year occur three months (13 weeks) apart: in January, April, and July. Common years starting on Monday share this characteristic, in the months of February, March, and November.

A leap year starting on Saturday is any year with 366 days (i.e. it includes 29 February) that begins on Saturday, 1 January, and ends on Sunday, 31 December. Its dominical letters hence are BA. The most recent year of such kind was 2000, and the next one will be 2028 in the Gregorian calendar or, likewise 2012 and 2040 in the obsolete Julian calendar. In the Gregorian calendar, years divisible by 400 are always leap years starting on Saturday. The most recent such occurrence was 2000 and the next one will be 2400, see below for more.

Any leap year that starts on Saturday has only one Friday the 13th: the only one in this leap year occurs in October. Common years starting on Sunday share this characteristic, but also have another in January. From August of the common year preceding that year until October in this type of year is also the longest period (14 months) that occurs without a Friday the 13th. Common years starting on Tuesday share this characteristic, from July of the year that precedes it to September in that type of year.

A common year starting on Sunday is any non-leap year (i.e. a year with 365 days) that begins on Sunday, 1 January, and ends on Sunday, 31 December. Its dominical letter hence is A. The most recent year of such kind was 2023, and the next one will be 2034 in the Gregorian calendar, or, likewise, 2018 and 2029 in the obsolete Julian calendar, see below for more.

Any common year that starts on a Sunday has two Friday the 13ths: those two in this common year occur in January and October.

A common year starting on Monday is any non-leap year (i.e., a year with 365 days) that begins on Monday, 1 January, and ends on Monday, 31 December. Its dominical letter hence is G. The most recent year of such kind was 2018, and the next one will be 2029 in the Gregorian calendar, or likewise, 2019 and 2030 in the Julian calendar, see below for more. This common year is one of the three possible common years in which a century year can begin on and occurs in century years that yield a remainder of 300 when divided by 400. The most recent such year was 1900, and the next one will be 2300.

Any common year that starts on Monday has two Friday the 13ths: those two in this common year occur in April and July.From July of the year in this type of year to September in the year that follows this type of year is the longest period that occurs without a Friday the 13th, unless the following year is a leap year starting on Tuesday, in which case the gap only 11 months, as the next Friday the 13th is already in June.

A common year starting on Tuesday is any non-leap year (i.e. a year with 365 days) that begins on Tuesday, 1 January, and ends on Tuesday, 31 December. Its dominical letter hence is F. The most recent year of such kind was 2019, and the next one will be 2030, or, likewise, 2025 and 2031 in the obsolete Julian calendar, see below for more.

Any common year that starts on Tuesday has two Friday the 13ths: those two in this common year occur in September and December. Leap years starting on Monday share this characteristic. From July of the year preceding this year until September in this type of year is the longest period (14 months) that occurs without a Friday the 13th. Leap years starting on Saturday share this characteristic, from August of the common year that precedes it to October in that type of year.

A leap year starting on Monday is any year with 366 days (i.e. it includes 29 February) that begins on Monday, 1 January, and ends on Tuesday, 31 December. Its dominical letters hence are GF. The most recent year of such kind was 2024, and the next one will be 2052 in the Gregorian calendar or, likewise, 2008 and 2036 in the obsolete Julian calendar.

Any leap year that starts on Monday has two Friday the 13ths: those two in this leap year occur in September and December. Common years starting on Tuesday share this characteristic.

A common year starting on Wednesday is any non-leap year (a year with 365 days) that begins on Wednesday, January 1, and ends on Wednesday, December 31. Its dominical letter hence is E. The current year, 2025, is a common year starting on Wednesday in the Gregorian calendar, and the next such year will be 2031, or, likewise, 2015 and 2026 in the obsolete Julian calendar, see below for more. This common year is one of the three possible common years in which a century year can begin on, and occurs in century years that yield a remainder of 200 when divided by 400. The most recent such year was 1800, and the next one will be 2200.

Any common year that starts on Wednesday has only one Friday the 13th: the only one in this common year occurs in June. Leap years starting on Tuesday share this characteristic.

A common year starting on Thursday is any non-leap year (i.e. a year with 365 days) that begins on Thursday, 1 January, and ends on Thursday, 31 December. Its dominical letter hence is D. The most recent year of such kind was 2015, and the next one will be 2026 in the Gregorian calendar or, likewise, 2021 and 2027 in the obsolete Julian calendar, see below for more.

This is the only common year with three occurrences of Friday the 13th: those three in this common year occur in February, March, and November. Leap years starting on Sunday share this characteristic, for the months January, April and July. From February until March in this type of year is also the shortest period (one month) that runs between two instances of Friday the 13th. Additionally, this is the one of only two types of years overall where a rectangular February is possible, in places where Sunday is considered to be the first day of the week. Common years starting on Friday share this characteristic, when Monday is considered to be the first day of the week.