Common year starting on Thursday

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^[1] 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, but only in places where Monday is considered to be the first day of the week.

In the (currently used) Gregorian calendar, alongside Tuesday, the fourteen types of year (seven common, seven leap) repeat in a 400-year cycle (20871 weeks). Forty-four common years per cycle or exactly 11% start on a Thursday. The 28-year sub-cycle only spans across century years divisible by 400, e.g. 1600, 2000, and 2400.

This type of year has 53 weeks in the week-day format of the ISO 8601 standard.

In the now-obsolete Julian calendar, the fourteen types of year (seven common, seven leap) repeat in a 28-year cycle (1461 weeks). A leap year has two adjoining dominical letters (one for January and February and the other for March to December, as 29 February has no letter). This sequence occurs exactly once within a cycle, and every common letter thrice.

As the Julian calendar repeats after 28 years that means it will also repeat after 700 years, i.e. 25 cycles. The year's position in the cycle is given by the formula ((year + 8) mod 28) + 1). Years 3, 14 and 20 of the cycle are common years beginning on Thursday. 2017 is year 10 of the cycle. Approximately 10.71% of all years are common years beginning on Thursday.

• • Valentine's Day falls on a Saturday
  • World Day for Grandparents and the Elderly falls on July 26
  • Halloween falls on a Saturday
  • Christmas Day falls on a Friday

• • Epiphany falls on a Tuesday
  • Candlemas falls on a Monday
  • Saint Joseph's Day falls on a Thursday
  • The Annunciation of Jesus falls on a Wednesday
  • The Nativity of John the Baptist falls on a Wednesday
  • The Solemnity of Saints Peter and Paul falls on a Monday
  • The Transfiguration of Jesus falls on a Thursday
  • The Assumption of Mary falls on a Saturday
  • The Exaltation of the Holy Cross falls on a Monday
  • All Saints' Day falls on a Sunday
  • All Souls' Day falls on a Monday
  • The Feast of Christ the King falls on November 22 (or on its earliest possible date of October 25 in versions of the calendar between 1925 and 1962)
  • The First Sunday of Advent falls on November 29
  • The Immaculate Conception falls on a Tuesday
  • Gaudete Sunday falls on December 13
  • Rorate Sunday falls on December 20

• • Australia Day falls on a Monday
  • Waitangi Day falls on a Friday
  • Daylight saving ends on April 5
  • ANZAC Day falls on a Saturday
  • Mother's Day falls on May 10
  • Father's Day falls on September 6
  • Daylight saving begins on September 27 in New Zealand and October 4 in Australia

• • Saint David's Day falls on a Sunday
  • Mother's Day falls on its earliest possible date of March 1, or on March 8, March 15, March 22 or March 29
  • Saint Patrick's Day falls on a Tuesday
  • Daylight saving begins on March 29
  • Saint George's Day falls on a Thursday
  • Father's Day falls on its latest possible date, June 21. This is only common year when Father's Day falls on ISO week 25. It falls on ISO week 24 in all othe common years. However, both leap year starting on Thursday and leap year starting on Wednesday share this characteristic.
  • Orangeman's Day falls on a Sunday
  • Daylight saving ends on its earliest possible date, October 25
  • Guy Fawkes Night falls on a Thursday
  • Saint Andrew's Day falls on a Monday

• • Daylight saving begins on its earliest possible date, March 8
  • Mother's Day falls on May 10
  • Victoria Day falls on its earliest possible date, May 18
  • Father's Day falls on its latest possible date, June 21
  • Canada Day falls on a Wednesday
  • Labour Day falls on its latest possible date, September 7 – this is the only common year when Victoria Day and Labour Day are sixteen weeks apart (they are fifteen weeks apart in all other common years)
  • Thanksgiving Day falls on October 12
  • Daylight saving ends on its earliest possible date, November 1

• • Martin Luther King Jr. Day falls on January 19
  • President's Day falls on February 16
  • Daylight saving begins on its earliest possible date, March 8
  • Mother's Day falls on May 10
  • Memorial Day falls on its earliest possible date, May 25
  • Juneteenth falls on a Friday
  • Father's Day falls on its latest possible date, June 21
  • Independence Day falls on a Saturday
  • Labor Day falls on its latest possible date, September 7 – this is the only common year when Memorial Day and Labor Day are fifteen weeks apart (they are fourteen weeks apart in all other common years)
  • Grandparents' Day falls on its latest possible date, September 13
  • Columbus Day falls on October 12
  • Daylight saving ends on its earliest possible date, November 1
  • Thanksgiving Day falls on November 26