ROCKPORT — Bay Chamber Concerts & Music School has announced its summer concert season for 2015, the nonprofit organization's 55th year of presenting top-tier classical, jazz and world music to Midcoast audiences.

The Summer Concert Series will run July 9 through Aug. 14, with performances every Thursday evening at the Rockport Opera House and Friday nights in Union Hall. Immediately following the series is the Summer Music Festival, a five-day musical extravaganza Aug. 19 through 23. Full program details, discounted ticket packages and single tickets are available at baychamberconcerts.org.

Bay Chamber's artistic director Manuel Bagorro has programmed a mix of traditional and boldly adventurous programming. In addition to favorite returning artists including Brooklyn Rider, Latitude 41, Decoda, James Austin Smith, Geoff Nuttall, Christopher Costanza, Livia Sohn and Alessio Bax, Bay Chamber will introduce new gifted musicians including soprano Julia Bullock, violinist Bella Hristova, Aeolus Quartet, Trio con Brio Copenhagen and clarinetist Alexander Fiterstein.

Thursday evening performances take place in the Rockport Opera House, where all seating is reserved, at 7:30 p.m. The casual Friday Night Café concerts in Union Hall offer more interactive and adventurous musical experiences, often including lighter repertoire. General admission seating is arranged around intimate tables, with select beverages available for purchase. Most Friday performances begin at 9 p.m., making it a popular after-dinner event; on July 10 and Aug. 7, there will be 6 p.m. performances, as well.

"What makes Bay Chamber Concerts unique is our creative, informal approach to presenting great music," said Bagorro in a news release. "Performances in Union Hall feel like gatherings of friends; Rockport Opera House has the atmosphere of an elegant European recital room; our summer festival is an exuberant celebration of music making at the highest level.

The Summer Music Festival, in various venues in Rockport, includes the popular Bach for Breakfast series in Pascal Hall; midday events including an intimate and interactive opera; early evening concerts at the Rockport Opera House; and nighttime performances in Union Hall. The festival also will present the world premiere of another Bay Chamber Commission, Marriage Suites.

In addition to the Summer Concert Series and Summer Music Festival, Bay Chamber Concerts also will present a free outdoor jazz concert featuring the Creative Ensemble Collective Sunday, Aug. 16, at 4 p.m. at Rockport Marine Park. And BCC's tradition of providing musical performances to island residents continues, with a concert Aug. 12 on North Haven and Aug. 18 on Vinalhaven.

The final event of the summer will be a gala reception and season finale at Brewster Point. Directed by Los Angeles-based director, production designer and visual artist James Darrah, the evening's performance will include music by Vivaldi, Bach and a contemporary one-act opera by Jonathan Dove titled L'Altra Euridice featuring baritone Douglas Williams.

As part of Bay Chamber Concerts' effort to make live music performances more accessible to younger audiences, all tickets for those younger than 25 are $10 for anyone younger than 25. Single ticket prices for those older are $45 for the Thursday Night Series, $35 for Friday Night Café. Discounted subscriptions and packages, summer program details and single tickets are available at baychamberconcerts.org or by calling 236-2823.