Here is a sample from the data that I am looking at.
Hour Index Visits 0 67 1 22 2 111 3 22 4 0 5 0 6 22 7 44
Please try: =UPPER(TEXT(DAY(2+A2/24),"ffffdd")). The first 2 is to control when the sequence starts.
=UPPER(TEXT(DAY(2+A2/24),"ffffdd"))
2