The boys participated in Shave for a Cure, the annual Leukaemia & Blood Cancer New Zealand fundraising event which supports patients and their families living with a blood cancer or a related blood condition.
''A few of the boys have definitely been noticing the cold,'' head boy Max Chu said.
''Personally, I've had a lot of hair my whole life.
''My dad's bald and when he said it would be colder, I thought he was joking. But he was right.''
Max said hats had suddenly become popular at school.
The school has raised $18,448 so far - the second-highest amount amassed by a New Zealand school.
Bucklands Beach Intermediate heads it with $19,146.
But Max was confident Otago Boys' would beat the Auckland intermediate school when he put a further $2500 in the account later this week.
St Hilda's Collegiate School, Columba College and Otago Girls' High School had also contributed money to the Otago Boys' campaign.
''It was definitely a Dunedin school community project.''
He said the cause was important to him because his grandfather died of cancer last year.
''I wasn't able to attend the funeral because I was overseas at the time. So this is my way of giving back.''
Everyone who participated had similar stories, he said.
