The date is coded as a 2-digit month and a single letter week. Some plants would pad a single digit month with a leading zero (0), some such as Fremont did not. Fremont would sometimes have a space between the month and week such as 5 E and sometimes not such as 6C.
Number | Month | Number | Month |
01 | January | 07 | July |
02 | February | 08 | August |
03 | March | 09 | September |
04 | April | 10 | October |
05 | May | 11 | November |
06 | June | 12 | December |
The week letter typically ranges from A to D and an occasional week letter E has been found. The letter "A" is the first week, the letter "B" is the second week, etc. However, there is not a direct correlation between a week letter and specific days or a physical week of any given month and each plant seemed to have their own standard operating procedures explaining why some plants for a given month may have the letter "E" for a fifth week when other plants do not for that month.