“To me now it’s outdoor Shanghai, and then you come over here and maybe play one or two max, maybe three with the World Tour Finals,” Federer said, adding, “But still, nevertheless, I mean, I enjoy playing the indoor season as much as I can because that’s what I did very often when I was younger in February, and then also at the end of the year.”

Andy Murray, who played much of his early tennis in his native Scotland, where the cold mist kept him inside for much of the year, still plays frequently indoors. This fall, he won in Vienna and Valencia before reaching the quarterfinals in Paris.

“I guess it’s like some of the Spaniards growing up on clay,” he said. “I grew up on indoor hardcourts. So that would be my most natural surface, really.”

Murray said a roof had a way of intensifying a match.

“I always think if you get a good atmosphere indoors, you feel it more because you don’t lose any of the noise out of the stadium,” he said. “Everything stays inside, and it always seems like it’s a bit louder.”

Chris Evert, a Floridian who said she thought she had an advantage when outdoor matches brought heat, wind, and rain, nevertheless fondly recalled playing in Madison Square Garden.

“You can really hear the emotions of the crowd,” she said. “You can feel them in outdoors, but you could hear them also in indoors. Every rustle, every noise comes out magnified. There’s a little more feeling of anticipation and excitement indoors than there is outdoors.”

The Garden, once a home to both tours, now hosts tennis for one night a year, and it is only an exhibition. There are no more indoor tournaments in Los Angeles, San Jose or Philadelphia, either. Aside from the year-end finals on both tours, the only large tournament held indoors on either tour is the Paris Masters.