Leap year starting on Thursday

Leap years that begin on Thursday, along with those that start on Monday or Saturday, occur least frequently: 13 out of 97 (≈ 13.402%) total leap years in a 400-year cycle of the Gregorian calendar. Their overall occurrence is 3.25% (13 out of 400).

For this kind of year, the corresponding ISO year has 53 weeks, and the ISO week 10 (which begins March 1) and all subsequent ISO weeks occur earlier than in all other years, and exactly one week earlier than common years starting on Friday, for example, June 20 falls on week 24 in common years starting on Friday, but on week 25 in leap years starting on Thursday, despite falling on Sunday in both types of year. That means that moveable holidays may occur one calendar week later than otherwise possible, e.g. Gregorian Easter Sunday in week 17 in years when it falls on April 25 and which are also leap years, falling on week 16 in common years.[2]

400 year cycle

century 1: 4, 32, 60, 88

century 2: 128, 156, 184

century 3: 224, 252, 280

century 4: 320, 348, 376

Like all leap year types, the one starting with 1 January on a Thursday occurs exactly once in a 28-year cycle in the Julian calendar, i.e. in 3.57% of years. 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).

Wikimedia Commons has media related to Leap years starting on Thursday and ending on Friday.

• • Valentine's Day falls on a Saturday
  • The leap day (February 29) falls on a Sunday
  • World Day for Grandparents and the Elderly falls on July 25
  • Halloween falls on a Sunday
  • Christmas Day falls on a Saturday

• • Epiphany falls on a Tuesday
  • Candlemas falls on a Monday
  • Saint Joseph's Day falls on a Friday
  • The Annunciation of Jesus falls on a Thursday
  • The Nativity of John the Baptist falls on a Thursday
  • The Solemnity of Saints Peter and Paul falls on a Tuesday
  • The Transfiguration of Jesus falls on a Friday
  • The Assumption of Mary falls on a Sunday
  • The Exaltation of the Holy Cross falls on a Tuesday
  • All Saints' Day falls on a Monday
  • All Souls' Day falls on a Tuesday
  • The Feast of Christ the King falls on November 21 (or on its latest possible date of October 31 in versions of the calendar between 1925 and 1962)
  • The First Sunday of Advent falls on November 28
  • The Immaculate Conception falls on a Wednesday
  • Gaudete Sunday falls on December 12
  • Rorate Sunday falls on December 19

• • Australia Day falls on a Monday
  • Waitangi Day falls on a Friday
  • Daylight saving ends on April 4
  • ANZAC Day falls on a Sunday, and in some years coincides with Easter Sunday falling on its latest possible date
  • Mother's Day falls on May 9
  • Father's Day falls on September 5
  • Daylight saving begins on September 26 in New Zealand and October 3 in Australia

• • Saint David's Day falls on a Monday
  • Mother's Day falls on March 7, March 14, March 21, March 28 or on its latest possible date of April 4
  • Daylight saving begins on March 28
  • Saint Patrick's Day falls on a Wednesday
  • Saint George's Day falls on a Friday, and in some years coincides with Good Friday falling on its latest possible date
  • Father's Day falls on June 20
  • Orangeman's Day falls on a Monday
  • Daylight saving ends on its latest possible date, October 31
  • Guy Fawkes Night falls on a Friday
  • Saint Andrew's Day falls on a Tuesday

• • Daylight saving begins on its latest possible date, March 14
  • Mother's Day falls on May 9
  • Victoria Day falls on its latest possible date, May 24
  • Father's Day falls on June 20
  • Canada Day falls on a Thursday
  • Labour Day falls on September 6
  • Thanksgiving Day falls on October 11
  • Daylight saving ends on its latest possible date, November 7

• • Martin Luther King Jr. Day falls on January 19
  • President's Day falls on February 16
  • Daylight saving begins on its latest possible date, March 14
  • Mother's Day falls on May 9
  • Memorial Day falls on its latest possible date, May 31
  • Juneteenth falls on a Saturday
  • Father's Day falls on June 20
  • Independence Day falls on a Sunday
  • Labor Day falls on September 6
  • Grandparents' Day falls on September 12
  • Columbus Day falls on October 11
  • Election Day falls on its earliest possible date, November 2
  • Daylight saving ends on its latest possible date, November 7
  • Thanksgiving Day falls on November 25