Typo in third sentence corrected 18 April 2011
Choose the year, and look at Table 1. Make a note of the J number in the last column. If the year is a leap year (marked L), look for the date in Table 3 (note that 1900 is not a leap year). Otherwise look for the date in Table 2. Make a note of the D number in the last column.

The weekdays are numbered as:

1 or 8: Sunday, 2 or 9: Monday, 3 or 10: Tuesday, 4 or 11: Wednesday, 5 or 12: Thursday, 6 or 13: Friday, 7: Saturday

Then the desired weekday has the number J + D

Table 1. Years

Table 2. Dates in ordinary years

Table 3. Dates in leap years


Example

Part of a 1912 Diary

For 1912, Table 1 gives J = 1 and the L means it is a leap year. Then Table 3 for 26 September gives D = 4. Then J + D = 5, indicating Thursday, as in the picture.

Last updated: 18 April 2011