For the past 11 years, partner "Bubs" Findlay has joined him, and the pair spend three weeks in their little old caravan, among a group of friends.
The great weather was one of the main reasons they enjoyed their holidays at Clyde, as well as catching up with old friends.
They don't have the "mod cons" that many people have with their new caravans, but they make do, Mrs Findlay said.
"When I first came here with Dave I thought `Lordy, Lordy', as the van was so small; but I have found a place for everything."
They eat Christmas dinner with their extended family, who also camp at Clyde; and celebrate New Year's Eve with their extended group and family.
Mr Muir is well known around the camp as the "fix-it man".
"If something breaks in one of the caravans they come to Dave for a spare nut or a screw. He's got a bag of nuts and bolts he's been carrying around for years, and it really comes in handy," Mrs Findlay said.
The couple enjoy sitting with their friends and having a wine or two in the evening.
Their friend Dorothy Rolleston from Mosgiel and her husband used to camp next door.
When Mrs Rolleston's husband died three years ago she was going to sell her caravan.
But Mr Muir and Mrs Findlay wouldn't hear of it.
Each year they bring her caravan to the site and have it all set up for her when she arrives.
They usually stay for three weeks - but if the weather "packs up", they go home.
