Heavy rain lashed down in the gardens on Tuesday as 8,000 guests gathered to meet the King and Queen as well as the Princess Royal.
Camilla told one attendee she was “remarkably dry” as party-goers huddled under umbrellas to keep out of the rain.
Among those speaking to the King was Sandy McPherson, who attended with his wife Catherine and granddaughter Sarah.
Mrs McPherson said: “Well, it’s good for the ground.”
Mr McPherson added: “It’s not rain, it’s next year’s whisky!”
He received an award from the Lord Provost of Edinburgh for good citizenship and told the PA news agency the King commented on his tartan, which was a hunting McPherson tartan.
He said: “It’s good for hunting or being hunted.”
First Minister Humza Yousaf was also at the garden party, sporting a Palace of Holyroodhouse umbrella to fend off the rain.
Also in attendance were volunteers from the Royal National Lifeboat Institution (RNLI), who said they were used to the weather “365 days a year”.
Douglas Munro, a volunteer based at North Kessock in Inverness, said the King asked them about their ranks and was “very knowledgeable” about their work.
He joked: “Unfortunately we didn’t bring our boat with us today, which would have been useful for a day like this.”
His colleague Douglas Grant said: “We’re used to this kind of weather, 365 days a year we are on service and we are used to this kind of weather.”
The annual garden party was held as part of Royal Week in Scotland where the royal family hosts guests who have made a contribution to their communities.
On Wednesday, the King will receive the Scottish crown jewels in a service of thanksgiving at St Giles’ Cathedral in Edinburgh.