A leap year starting on Wednesday is any year with 366 days (i.e. it includes 29 February) that begins on Wednesday 1 January and ends on Thursday 31 December. Its dominical letters hence are ED. The most recent year of such kind was 2020 and the next one will be 2048 in the Gregorian calendar, or likewise, 2004 and 2032 in the obsolete Julian calendar, see below for more.^[1]

Any leap year that starts on Monday, Wednesday or Thursday has two Friday the 13ths: those two in this leap year occur in March and November. Common years starting on Thursday share this characteristic, but also have another in February.

Leap years starting on Sunday also share a similar characteristic to this type of leap year, three Friday the 13th's have a three month gap between them, the former two being in the common year preceding this type of leap year, those being September and December, and the latter being in this type of year, that being March. Leap years starting on Sunday share this by having January, April and July three months apart from each other.

This is the only leap year with three occurrences of Friday the 17th: those three in this leap year occur three months (13 weeks) apart: in January, April, and July. Common years starting on Sunday share this characteristic, in the months of February, March, and November.

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 Tuesday the 13th as in 2019-20. Common years starting on Saturday share this characteristic, from July of the year that precedes it to September in that type of year.

If this year occurs, the leap day falls on a Saturday (similar to its common year equivalent), transitioning it from what it would appear to be a common year starting on Wednesday to the next common year after the previous one, so March 1 would start on a Sunday, like it would be on its common year equivalent (March to December of this type of year aligns with the common year equivalent, that may have happened 5 years earlier.) The previous leap year would have to have been on a Friday due to the Gregorian Calendar's cyclical nature.

Leap years that begin on Wednesday, along with those starting on Tuesday, occur at a rate of approximately 14.43% (14 out of 97) of all total leap years in a 400-year cycle of the Gregorian calendar. Thus, their overall occurrence is 3.5% (14 out of 400).

For this kind of year, the corresponding ISO year has 53 weeks.

Like all leap year types, the one starting with 1 January on a Wednesday 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 Wednesday and ending on Thursday.

• • Valentine's Day falls on a Friday
  • 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 Monday
  • Candlemas falls on a Sunday
  • 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 Sunday
  • Waitangi Day falls on a Thursday
  • 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
  • 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. This is the only leap year when Victoria Day and Labour Day are 34 days apart. They are 27 days apart in all other leap years.
  • Canada Day falls on a Wednesday
  • Labour Day falls on its latest possible date, September 7 – this is the only leap year when Victoria Day and Labour Day are sixteen weeks apart (they are fifteen weeks apart in all other leap years)
  • Thanksgiving Day falls on October 12
  • Daylight saving ends on its earliest possible date, November 1 -This is the only leap year when Labour Day and the end of Daylight Saving Time are 55 days apart. They are 62 days apart in all other leap years

• • Martin Luther King Jr. Day falls on January 20
  • President's Day falls on February 17
  • 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. This is the only leap year when Memorial Day and Father’s Day are 27 days apart. They are 20 days apart in all other leap years. This is also the only leap year when the start of Daylight Saving Time and Father’s Day are 15 weeks apart. They are 14 weeks apart in all other leap years
  • Independence Day falls on a Saturday
  • Labor Day falls on its latest possible date, September 7 – this is the only leap year when Memorial Day and Labor Day are fifteen weeks apart (they are fourteen weeks apart in all other leap years). This is the only leap year when the start of Daylight Saving Time and Labor Day are 183 days apart. They are 176 days apart in all other leap years.
  • Grandparents' Day falls on its latest possible date, September 13. This is the only leap year when Memorial Day and Grandparent’s Day are 111 days apart. They are 104 days apart in all other leap years. This is also the only leap year when the start of Daylight Saving Time and Grandparent’s Day are 27 weeks apart. They are 26 weeks apart in all other leap years
  • Columbus Day falls on October 12
  • Daylight saving ends on its earliest possible date, November 1. This is the only leap year when Labor Day and the end of Daylight Saving Time are 55 days apart. They are 62 days apart in all other leap years. This is also the only leap year when Father’s Day and the end of Daylight Saving Time are 19 weeks apart. They are 20 weeks apart in all other leap years. This is also the only leap year when Grandparent’s Day and the end of Daylight Saving Time are 7 weeks apart. They are 8 weeks apart in all other leap years
  • Election Day falls on November 3, its 2nd earliest election day, only surpassed by November 2.
  • Thanksgiving Day falls on November 26