The calendar, which detailed other international festivals, such as the Chinese, Islamic and Jewish new years, as well as St Andrew's Day and St George's Day, featured on a leaflet outlining local leisure services.
The council apologised to residents for failing to include the Welsh patron saint's day and has ended its contract with Leisure Information Services.
A spokesperson for the company told printweek.com: "We were given a file to print and we printed it", but declined to comment further.
Gareth Jones, Ceredigion council's director of education, told printweek.com the printer supplied a "blueprint" of what it could produce, which "made it even more confusing" when the calendars arrived.
He added that "it was too early" for the council to decide on a new printer to carry out the work in future.
A council spokesperson said: "We checked other directories produced by the company and St David's Day has been listed in all. This is indeed an error."
Have your say in the Printweek Poll
Related stories
Latest comments
"Thank you for the opportunity to comment on this Jo, and PrintWeek!
Please feel free to get in touch with the Howden Print Team to arrange your own Free of Charge Cyber Micro-Penetration Test to help..."
"I never quite understand the statements such as "achieved such a positive outcome for this well-established business".
The established business unfortunately failed and no longer exists, a..."
"Genuinely sorry to read this."
Up next...

Commitment, presence and energy will be much missed
Tributes paid to Lascelle Barrow

Around 300 roles may be affected
International Paper to close five UK packaging sites

Asset ownership delayed process
Reflections to be liquidated

'Start of a new era'