Fifty people, including veterans, turned up for a remembrance parade a week early after road closure signs showed the wrong date.
The signs in Shotton, Flintshire, said the event was on 7 November, instead of 14 November.
Local councillor Bernie Attridge called it "incompetence," saying some people were upset, and he wants an apology from Flintshire council officials.
The council apologised and said the mistake was "extremely regrettable".
Mr Attridge, who represents Connah's Quay Central, said he was alerted to the signs on Saturday morning, and telephoned the council to demand they were taken down.
"The damage had already been done," said Mr Attridge.
"I went to the cenotaph on Sunday and I was amazed at how many people had seen the signs.
"There was one chap there in full military uniform. One woman was in tears. She had lost her son in conflict and religiously goes to military services.
"She said Remembrance parades are hard enough, and to have this on top is awful.
"Having seen the signs, she presumed the service had been moved forward."
He added: "I was livid.
"At first I thought it was a sick joke and someone had put a few signs up.
"How could they get it so wrong? It's madness."
Cllr Attridge questioned the cost of producing and distributing signs, adding: "It's total incompetence."
Neal Cockerton, head of assets and transportation at Flintshire council, said: "The signs were placed out on Friday and withdrawn on Saturday morning when we were made aware of the mistake.
"The error is extremely regrettable and we apologise for this mistake and any distress it may have caused."