There was quite a buzz amongst Winnipeggers around the opening of Rainbow Stage in the early 1950's, according to photos and articles from the Winnipeg Free Press archives:

Free Press archives - construction 1952: An article detailing the beginning of construction of Rainbow Stage in 1952

Giant Outdoor Theatre to Rise This Summer A Kildonan Park

Construction of a giant summer theatre for Winnipeggers, similar in many respects to Vancouver’s Theatre Under the Stars will be carried out this summer in Kildonan park.  It was announced Friday by Reg. Hugo, honorary chairman of the Rainbow Stage Campaign committee.

A stage as wide and as deep as in the civic auditorium will be large enough to accommodate performances of a full-sized symphony orchestra, or will house the full cast of a large musical comedy, Mr. Hugo said.

The theatre will get its name from the rainbow shape of the proscenium which will curve around the ceiling line of the stage.

Free Press archives - photo 1952: Model of the Rainbow Stage theatre published in the Winnipeg Free Press in 1952, two years before its opening.

Caption reads: "This model of the Winnipeg's Rainbow Stage to be built this summer in Kildonan Park will be on display at the Red River exhibition at the amphitheatre June 14 - 21.  A Free Press artist has given an idea of how he imagines the stage will look with an orchestra performing."

Free Press archives - July 7, 1954: An article published in the Winnipeg Free Press about the opening of Rainbow Stage on July 7, 1954

Rainbow Stage Opener to Star Local Talent
Local talent will be featured at the official opening of Winnipeg’s new Rainbow Stage at 8:15p.m. tonight.
Mayor Garnet Coulter will open Winnipeg’s first outdoor theatre before and expected crowd of 4,500 at Kildonan Park.
A varied program of Sunday concerts, Friday films, music and drama is being planned for other summer concerts.
Highlights of tonight’s program include a chorus by the Ukrainian Youth Association and Ukrainian national folk dances directed by Wally Uric.
Eric Wild and his presentation orchestra with Maxine Ward and the James Duncan Chorus will present a selection of popular tunes. 

Free Press archives - opening night: Photo from the opening night of Rainbow Stage in 1954, published in the Winnipeg Free Press on July 8, 1954.  The opening paragraph of the Article below (bottom right) Reads: Singing, dancing colorful costumes and fresh air proved to be an irresistible mixture at the opening program of the Rainbow Stage at Kildonan Park Wednesday."

4,500 Attend Gala Stage Opening!