Balmy weather might be expected to add to the appeal of a visitor’s first trip to New York City, but, for Elina Garanca, it felt like nothing but trouble. The 31-year-old Latvian mezzo soprano, who has excited European audiences from Vienna to London, arrived earlier this week to prepare for her American debut on Saturday evening as Rosina in the Metropolitan Opera’s production of “Il Barbiere di Siviglia.” Like any conscientious singer, she was less inclined to enjoy the spring-like breezes than concerned with how the fluctuation in temperature would affect her health. “It’s gone from minus 10 to plus 17,” she said, referring to Celsius degrees, “and I am sensitive to air-conditioning.”

But Ms. Garanca (pronounced Garansha) should, by now, be used to adapting to an environment. In October she returned to Latvia to sing her first Carmen, with the opera company in Riga, and in November she sang her first Adalgisa, opposite Edita Gruberova’s Norma in Munich. Indeed, her repertory is marked by an extraordinary versatility, as is demonstrated by her first solo disc for Deutsche Grammophon, which spans Spanish zarzuelas and the final scene from “Der Rosenkavalier,” with French and Italian arias in between. In an earlier solo disc for Virgin Classics she even sang soprano arias.

Bartlett Sher’s production of “Il Barbiere di Siviglia” was one of the hits of Peter Gelb’s first Metropolitan Opera season, and, with Ms. Garanca’s appearance, promises to be no routine revival. She has won high marks for the beauty of her tone and eloquent musicianship, not to mention her blond good looks.

Speaking after a rehearsal of “Barbiere,” Ms. Garanca appeared to be energized by Mr. Sher’s lively production. “He is the kind of director I like to work with, who trusts the singer,” she said.

“Some have persuaded me to switch to being a soprano, but I don’t think so,” she said. For one thing, she regards soprano roles as too predictable. “Sopranos have affairs with the tenor and then die,” she said.

As a youngster in Riga, she developed an interest in musicals and in singers such as Barbra Streisand, Mariah Carey, and Freddie Mercury. “I went to ‘Tannhäuser’ when I was 7 and was so bored I had to leave.” But music was in her genes. Her mother is a singing teacher and her father a choral conductor, an upholder of the esteemed Baltic tradition.

After her conservatory studies, her career began in a time-honored way in a small German theater, that of Meiningen. But such a beginning, she points out, can be a mixed blessing. “Some singers start there and never leave,” she said, “and it is very bureaucratic.” After a year and a half, she moved on to Frankfurt for two years and then to the Vienna Staatsoper, where her career took off. She made her Salzburg debut in 2004 as Annio in Mozart’s “La Clemenza di Tito” but last year moved on to the role of Sesto, at Vienna’s Theater an der Wien.

She has already worked with some of the giants in the field, having toured with Mariss Jansons, whom she especially reveres. And she spoke of conductors Nikolaus Harnoncourt and Riccardo Muti. “Harnoncourt is a fascinating personality,” she said. “You may not agree with everything he does, but it always makes sense. Muti is a dream — he takes time to work with you in rehearsals on the smallest details.”

She believes the breadth of her repertoire helps prevent the burnout that sometimes afflicts singers whom the media discover early. “Mezzos are not as fast-blossoming as sopranos,” she said. “I can sing Cherubino half the time and Carmen the other half.”

“I disagree with Maestro Harnoncourt when he says that singers are like pigs in a slaughterhouse, some stamped for goulash, others for steak,” she added. “Once singers get stamped for roles and repertoire, singing becomes routine — and routine is the most horrible thing. You have to keep yourself alive.”

She sometimes is frustrated by stage directors whose background is in straight theater. “There are many different ways to say or scream or yell a word. But in opera, music must be the guiding line. You have to feel and understand the music. I like to be experimental, but I always have to ask, ‘Why?’ If I do something I am not convinced of, the audience will know.”

She will return to the Met next season in “La Cenerentola” and the following season she sings the Muse in a new production of “Les Contes d’Hoffmann” directed by Mr. Sher. Not surprisingly, she is attracted to the character’s music that is absent from the standard performing version that was long in use. “I don’t think there is anything more beautiful than the ‘Violin aria,'” she said, calling the apotheosis finale “absolutely essential.”

She admitted that the Met performances might be her farewell to the role of Rosina. “Rossini is a guy to keep the voice fit, but roles like Carmen and Charlotte suit me better,” she said of the role in “Werther.” She has her sights on Amneris in “Aida” and Eboli in “Don Carlo” but not for another decade. One thing, though, is sure: Ms. Garanca is not a singer to stagnate.