The presenter was merely a dark shadow at the beginning of his weather segment as he ran across the camera during the tail end of the news bulletin.
Jenny Suo called him out on his blunder, and the chaos didn't end there.
"I was actually listening to the news - Nah, I wasn't actually, I was waiting for Matty. Anticipating, waiting," joked Jenny-May Clarkson.
"Up to his usual professionalism," Suo said, and the presenters cracked up laughing.
"What was the issue? You seem to have plenty of time," Clarkson asked. And McLean tried to explain his way out of the on-air gaffe.
"You know when you're using technology, and you are needing something to work quickly, all of a sudden it decides to be as slow as it possibly can? Yeah, that's what happened this morning," he told Breakfast viewers.
But Suo wasn't having it: "Don't blame the technology Matty."
Clarkson urged viewers to "stay with us" as the team gathered composure. Unfortunately for Matty, that wasn't the end of the blunders.
McLean thanked the camera operator Pete for thinking ahead and putting out his broom for him.
His first weather photo failed to appear on the screen.
"The director said you need to click but I realised I hadn't put the weather warnings back in there," he explained when his fellow presenters asked if he was okay. "So I was trying to cover it up but, anyway...I've just exposed myself."
"John [Campbell] will be watching," he added. "You wait - there will be an email in seconds."
He tried his best to nail his pronunciations for Te Wiki o te Reo Māori, but when it came to pronouncing Whakaoriori, Masteron, he had difficulty and accidentally let a swear word slip.
"Where?" Clarkson queried when McLean attempted the pronunciation. He tried again and got it right eventually.
"That is the danger of te Reo Māori...if you stumble on the wrong word," McLean said.
Suo said his bulletin today was one to remember.
"Nice one Matty, I think you should clip that up and keep it in your archives," she said. "I and keep that to show your grandkids."
McLean walked off set, broom in tow, and admitted he had mistakenly omitted tomorrow's forecast from the end of his bulletin too.
Clarkson had some encouraging words for McLean: "I'll back you Matty. I'll back you every day of the week."