Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
0 | 3 | 3 | 6 | 1 | 4 | 6 | 2 | 5 | 0 | 3 | 5 |
- You must memorize this table. When you do, you will forget the number of the month itself (e.g., 6 for June) and know the month as its table value (4 for June). As with the other tables, one way to memorize the table is by some word as well as color associations and/or some mnemonics
You do not need to know the following to do the calculation of the Day-of-Week (etc.) but for those purists among our readers, here is some additional information.
- This is the table for every year, including leap years. The adjustment for the extra day in leap years due to 29 days in February is made elsewhere in the calculation. Were it not for this adjustment, the values for January and February for leap years would be 6 and 2 respectively.
- What is the meaning of the values in this table? The value for each month means how many days of the week removed from the day of the week of the first day of the year the first day of the week of that month is.
- How is this table derived? Given the meaning, the value of January is 0 (zero). Since we know that there are 31 days in January, that’s 3 days beyond 4 four full weeks of 28 days, so the value going into February is 3. Since there are four full weeks in February (except for leap years, but we adjust for that elsewhere), no extra days are added for March beyond the 3 we had going into February, so the value for March is 3 also. Since we know that in March there are 31 days, that’s 3 days of the week more that the monthly calendars are pushed forward, and so the 3 going into March plus the 3 from March means 6, so the value for April is 6. In April there are 30 days, 2 days beyond four full weeks. The 2 from April plus the 6 going into April yields 8, but taking out the 7 days of full weeks we do not need yields 1, the value for May. You go figure the rest.
