Winter’s here, and the time is right for Joseph Crnko to go into overdrive.

Crnko (pronounced “Crenko”) is Seattle Symphony Orchestra’s associate conductor for choral activities as well as music director of youth-oriented arts organization Northwest Choirs. Wearing those two hats makes him very busy during a time of year when much of Seattle expects to hear a chorus singing “hallelujah,” or perhaps the “Ode to Joy” or Benjamin Britten’s pealing “Wolcum Yole!”

Among Crnko’s overlapping duties in recent weeks have been rehearsals for Seattle Symphony Chorale’s huge role in SSO’s annual production of Handel’s “Messiah” (concerts were held last weekend); upcoming Chorale rehearsals for end-of-the-year performances of Beethoven’s Ninth Symphony; and multiple appear­ances, in different settings, for various age groups in Northwest Choirs.

This weekend, Crnko and the middle-school members of Northwest Boychoir — supplemented by adolescent boys and girls from another Northwest Choirs ensemble called Vocalpoint! Seattle — will be concluding its nine-performance run of seasonal favorite “A Festival of Lessons and Carols.”

Based on a traditional Christmas Eve service at King’s College in Cambridge, England, “Festival” is in its 34th year as a Seattle touchstone. Northwest Boychoir performs the concert Friday and Saturday at St. Mark’s Cathedral, and Sunday at Benaroya Hall. The Benaroya event includes musicians from Northwest Sinfonia, a collection of professional players from Seattle Symphony and elsewhere.

Crnko has been conducting the “Festival,” and Boychoir, for 29 years.

Comprised of nine biblical passages, each followed by a carol sung by a boys choir, the original “Festival of Lessons and Carols” is rooted in a historic — and moving — Anglican observance.

“The elemental part of the ‘Festival’ is probably centuries old,” says Crnko. “In the middle of the 20th century, it became popularized at King’s College through radio and television. It is, in essence, a church service, a series of nine biblical readings that tell the story of the Nativity. In our format, each reading is followed by a song sung by the Boychoir. Then the entire audience joins the choir in singing a traditional Christmas carol.”

Among the singers in the 80-member choir is Benjamin Richardson, 14.

In training with Crnko since age 5, Richardson joined the Boychoir at 9 and will go into Vocalpoint! next year.

Richardson is singing solo on opening song “Once In Royal David’s City,” based on Cecil Humphrey’s 1848 children’s poem.

“It’s a bit of pressure but really fun,” he says. “People like the concert because we get to sing a wide range of Christmas songs, from classics that everyone’s heard to a Latin song that’s new. If there’s a certain style of Christmas music you like, you’ll probably hear that.”

Looking ahead to Beethoven’s Ninth (Dec. 28-30, with a special presentation New Year’s Eve), Crnko will bring in past and present Vocalpoint singers to augment the all-vounteer Chorale. He’s enthusiastic about working with Seattle Symphony music director Ludovic Morlot, who will conduct the epic piece in Benaroya for the first time.

“We met and talked about Beethoven,” says Crnko. “Ludovic has a fresh and energized approach to the Ninth. It’s going to be a great production.”

Tom Keogh: tomwkeogh@gmail.com