Even worse than only one cool date each week in September is this first week in October – NONE!

We will take the opportunity to further explain when Half-BacK Days will end this century. 

Back on 8/25 we discovered that each month has its own curtain call.  For January, 1/31/16 and for February, 2/28/15.

The several formulae being used:

                d = 2y – m   OR   d + m= 2y (see 6/23/13)

There are limits on year, month, and day values:

                0 <= y <= 99  (only 100 years in a century!)

                1 <= m <= 12  (only 12 months in a year!)

                And day limits vary by month

                1 <= d <= 28 or 29 for February

                1 <= d <=30 for April, June, September, and November

                1 <= d <= 31 for January, March, May, July, August, October, and December

 To solve, pick a month and the appropriate day limit.

For March, d = 2y – m <= 31

                Or  2y – 3 <= 31

                Or  2y  <= 34

                Or y <= 17…  3/31/17  up 28 and back 14!

 March:                 3/31/17

April:                     4/30/17

May:                      5/31/18

June:                     6/30/18

July:                       7/31/19

August:                  8/30/19

September:          9/29/19

October:              10/30/20

November:         11/29/20

December:         12/30/21

So we can bid adieu to halfback days at the end of 2021!