Leclerc had a collision with Oscar Piastri on the damp first lap of the race before diving into the pits for a switch to intermediates, which proved to be slow as the crew wasn't ready with his tyres.
The team could do nothing about the damage to his floor, and data indicated that he gradually lost more downforce as the race progressed.
He tumbled down the order and, shortly after being demoted to 16th by rookie Liam Lawson, he was called in to retire the car.
Although it did rain again late in the race, it wouldn't have helped Leclerc's cause by that stage.
"Already at the first lap when we had the damage I could feel much more than the guys were telling me on the radio," he said.
"Initially it was five to 10 points [of downforce] was what I've been told, but obviously then we realised it was more than 60, and more than 60 is a different category. After that, after the first lap, it was all uphill.
"We were just waiting for some rain, to be honest. Obviously, it's very tricky to drive a car with 60 points less in the rain, but it also adds a lot of chaos, and you can do something different than others and maybe score one or two points.
"Every point counts, so we didn't want to give up too early. Then we understood that the rain wouldn't come, even though now it came, but it would have been too late."
Regarding the clash with Piastri, he said: "We were in wet conditions with slicks, it was such a slight touch but for some reason, it had huge consequences on my car, so a shame."
Leclerc's life was made even more difficult by his slow lap one pitstop, but he had no regrets about making a late call to come in.
"I did call for it, in the last corner, so very late," he said. "But obviously looking at the [weather] situation in the last corner I was very sure that even if we had lost five or six seconds at the pitstop, we would recover them during one lap easily.
"I expected to lose some time, we could have optimised it as a team just for the guys to be ready a little bit earlier in those types of situations, but apart from that I think it was the right choice."
Leclerc admitted that Zandvoort was one of the toughest race of what has already been a difficult season for him.
"In terms of results obviously with a DNF like this it's not good, but it's been an extremely difficult weekend," he said.
"In terms of balance, it is probably the most difficult weekend of the season and driveability of the car, so we need to look into it, because the last two or three races were getting better on that side of things - and for some reason it was not this weekend."
