Common year starting on Sunday

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 current year, 2023, is a common year starting on Sunday in the Gregorian calendar. The last such year was 2017 and the next one will be 2034 in the Gregorian calendar,[1] or, likewise, 2018 and 2029 in the obsolete Julian calendar, see below for more.

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

This is the only common year with three occurrences of Friday the 17th: those three in this common year occur in February, March, and November. Leap years starting on Wednesday 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 17th.