×
How to figure out any day of the week in your head
- Take the last two digits of the year.
- Divide by 4, discarding any fraction.
- Add the day of the month.
- Add the month's key value: JFM AMJ JAS OND 144 025 036 146
- Subtract 1 for January or February of a leap year.
- Add 0 for 1900's, 6 for 2000's, 4 for 1700's, 2 for 1800's; for other years, add or subtract multiples of 400.
- Add the last two digits of the year.
- Divide by 7 and take the remainder.
You'll get a number between 0 and 6, which will correspond to one of the weekdays Saturday-Friday
Credit to this site for this method