Warm nor'west temperatures were a God-send for a group of naked Cantabrians taking a polar plunge at a Canterbury beach today.

About 30 bare bums streaked across the beach in Spencerville about midday for the annual plunge.

Michael, who did not want his last name used, said it was his first time going "skinny dipping" in the winter.

"I normally have a mid-winter swim on my own, but not a skinny-dip. It always dismays me this business about nudity. People get all upset about naked bodies but I don't see it as a problem."

He expected to feel "liberated" after the dip, he said.

"And the weather couldn't be better."

Sandy, 16, said her mother was a member of the Free Beaches organisation which held the plunge each year and she had taken the plunge "quite a few times".

"I'm not sure why I do it. It's for celebrating the shortest day. Mum is a member of Free Beaches and I come along. It's just same as with clothes. (Nudity) is just normal for me. I have grown up with it."

Organiser and chairperson for Free Beaches, Beatrice, said the day had been "wonderful".

"I am really surprised how many people showed up - over 30 people. I think it gets more popular each years."

Free Beaches held been holding an annual mid-winter plunge for over 10 years - as well as a summer plunge, she said.

Everyone enjoyed a mulled wine after the cool dip.