Is there a single-word adjective that means 'of a specific day'?
The contexts I'm thinking of are in the Catholic Church, where particular days are designated as commemorations of one or more saints.
St Stephen is the _____ saint of the 26th of December.
An alternative context would be the feast day of a god in Classical times.
Socrates wrote a hymn to an unknown god, the _____ god of the day his trial was delayed by.
'Daily' doesn't work, because it implies that the event is repeated every 24 hours (daily bread).