Common year starting on Thursday

This is the calendar for any common year starting on Thursday, January 1 (dominical letter D). Examples include years 1970, 1981, 1987, 1998, 2009, 2015 and 2026 in the Gregorian calendar, 2037 and 2043 will also be this year type^[1] or 2010, 2021 and 2027 in the Julian calendar (see bottom tables).

This is the only common year with three occurrences of Friday the 13th, in February, March and November. The other type of year with three occurrences of Friday the 13th is a Leap year starting on Sunday which has three Friday the 13ths in January, April, and July. Also interestingly, with the exception of skipped leap years, leap years starting on Sunday falls exactly three years either side of two consecutive common years starting on Thursday; the most recent occurrence was 2012 between 2009 and 2015. 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.

In this common year, February is rectangular in calendar where weeks start on a Sunday, Martin Luther King Jr. Day is on January 19, Valentine’s Day is on a Saturday, President's Day is on February 17, Saint Patrick’s Day is on a Tuesday, Memorial Day is on its earliest possible date, May 25, U.S. Independence Day and Halloween are on a Saturday, Labor Day is on its latest possible date, September 7, Veterans Day is on a Wednesday, Thanksgiving is on November 26, and Christmas is on a Friday. This common year is also the only one where Memorial Day and Labor Day are not 14 weeks (98 days) apart: they are 15 weeks (105 days) apart in this common year. Leap years starting on Wednesday share this characteristic. Like leap years starting on Wednesday, this common year also has the shortest gap between Halloween (October 31) and the end of Daylight Saving Time in the US (November 1) by one day. Prior to 2007, this common year had the longest gap between the end of Daylight Saving Time in the US (October 25) and Halloween by 6 days.

A common year is a year with 365 days, i.e. not a leap year.

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

References

1. ↑ ^{1.0 1.1} "A common year beginning on Thursday", jonstlouis.htmlplanet.com, 2011, webpage: HTMcal^{[permanent dead link]}.
2. ↑ "Calendar in year 1803 (Russia)" (Julian calendar, starting Tuesday), webpage: Julian-1803 (Romania used Julian in 1919, when Russia adopted Gregorian).