Federer suffered a 6-3, 6-4, 6-2 loss in what could be his final ever appearance at Roland Garros. Nadal was in sensational form as he took a giant step towards a 12th French Open title.
However, the conditions were horrendous for both men as they had to battle the gusty wind.
At some stages in the match, visibility was reduced to just a couple of yards as the red dirt was blown around court Philippe-Catrier.
Federer acknowledges that it was the same for both of them and joked he will have to clean his eyes.
“It was just crazy, the thing,” Federer said.
“There I’ll have to clear my eyes to see what I’m eating tonight.
“You get to the point where you’re just happy to make shots. It’s that bad.
“You just don’t want to look ridiculous.”
Federer was also unsure about the decision to play both of the women’s semi-final matches earlier in the day.
Because of a congestion fixture list due to rain, tournament organisers made the WTA matches take place on the outer courts.
And barely any supporters turned up at the set time to watch the women in action, which took an edge out of the matches.
“It was tough for women to be scheduled on outer court at 11 in the morning,” he said.
“Maybe things have to start faster in Slams.”
Meanwhile, Nadal will face the winner of Novak Djokovic vs Dominic Thiem in the final on Sunday.
If world No 2 Nadal wins it will take his Grand Slam tally up to 18, just two behind Federer’s all-time record.