So if you get an extra midnight pulse (noise) or miss a midnight pulse you have to reprogram the PIC with a new date??
I would add two buttons; day+ and day-, and one LED. So if you inc or dec the day, the PIC stores the new day, and the LED then flashes the day; like day 24 it would flash "2" then "4".
That would be very simple in hardware, pretty simple in software, and completely remove any need to unplug/reprogram the PIC again as it will never get more than a couple days out from any typical fault or disconnect.