The story focuses on Jane Hudson (Katharine Hepburn), a single, middle-aged elementary school secretary (she refers to her position as "a fancy secretary") from Akron, Ohio. She is on her summer vacation and is now enjoying her lifelong dream of a vacation in Venice after saving up money for the past few years for the big trip. During the ride on a vaporetto to the Pensione Fiorini, she meets two fellow Americans, Lloyd (MacDonald Parke) and Edith (Jane Rose) McIlhenny. At the hotel, they are greeted by Signora Fiorini (Isa Miranda), a widow who transformed her home into a pensione after World War II. Also staying at the property are Eddie Yaeger (Darren McGavin), a young American painter studying art, and his wife Phyl (Mari Aldon).
Jane is also pestered off and on during her stay by a friendly young Italian street urchin, Mauro.
That evening, Jane walks to the Piazza San Marco, where the sight of so many couples leaves her slightly depressed. While seated in a café, she becomes aware of a solitary Italian man watching her and quickly leaves.
The following day, Jane goes shopping and sees a red glass goblet in the window of an antiques store. Upon entering she discovers that the owner, Renato de Rossi (Rossano Brazzi), is the very man from whom she fled the night before. He assures her that the goblet is an authentic 18th-century artifact, and she purchases it after he teaches her the art of bargaining. Hoping to see her again, Renato offers to search for a matching goblet. The next morning, Jane returns to the shop with Mauro and is disappointed to discover that Renato is not there. Jane then accidentally steps backward into a canal while filming de Rossi's shop.
That evening, he comes to her pensione and confesses his attraction for her. When Jane resists his advances, he warns her not to waste an opportunity for happiness, and she is about to agree to have dinner with him when the McIlhennys return from a shopping expedition on the island of Murano, during which they purchased a set of new red goblets similar to the one Jane bought. Renato realises that she thinks he has swindled her, but he assures her that some designs have been used for centuries on Murano and he insists that her goblet is an antique.
The two attend a concert at the piazza, where an orchestra plays the overture to La gazza ladra. When a flower seller approaches them, Renato is surprised when Jane chooses a simple gardenia instead of an orchid. Later, as the couple are wandering through the city, Jane accidentally drops her gardenia into a canal; despite much effort, Renato is unable to retrieve it for her. They return to the pensione, where he kisses her, and she responds passionately and murmurs, "I love you," before rushing off to her room. The next day, she treats herself to salon treatments and new clothes in anticipation of their date that evening. While she waits for him at the piazza, Renato's assistant Vito (Jeremy Spenser) arrives and inadvertently reveals that he is Renato's son. Stunned to discover Renato is married and has several children, Jane takes refuge in a bar where she encounters Phyl, who confides that her marriage is in trouble.
Upon returning to the pensione, Jane discovers Eddie is having an affair with Signora Fiorini. Renato arrives and tells her their relationship is none of her business. He admits he is married, but claims he and his wife are separated, a fact he concealed because he did not want to scare her away. He accuses her of being immature and unwilling to accept what she can have in reality instead of just longing for more. After dinner, Jane and Renato venture to Renato's apartment and their affair is consummated.
After spending time with Renato on the island of Burano, Jane, unwilling to remain in a relationship she knows is destined to end unhappily, decides to return home. Renato begs her to stay, but Jane insists it is better to leave the party before it ends. Although she asks him not to come to the train station, she hopes he will ignore her request. As the train begins to leave the station, Jane is thrilled to see Renato running toward it. He tries to hand her a package but the train is moving too quickly, so he opens it to reveal he had bought her another gardenia.
Arthur Laurents had written The Time of the Cuckoo specifically for Shirley Booth, who starred in the 1952 Broadway production and won the Tony Award for Best Performance by a Leading Actress in a Play for her performance. Producer Hal Wallis expressed interest in purchasing the film rights, but felt Booth was too old for the role, and envisioned Katharine Hepburn and Ezio Pinza in the leads. Ilya Lopert ultimately acquired the rights with the intention of casting Booth and hiring Anatole Litvak to direct. It later was reported she was negotiating with Daniel Mann instead, and Laurents would be adapting his play for the screen. Laurents' screenplay allegedly was unsatisfactory, and newly hired director David Lean tried to improve it with associate producer Norman Spencer and writers Donald Ogden Stewart and S.N. Behrman, without success. He finally brought in novelist H.E. Bates to collaborate with him.
Numerous names were mentioned in conjunction with the project before filming finally began. At one point producer Lopert considered casting director-actor Vittorio De Sica as Renato. Roberto Rossellini expressed interested in directing the film with Ingrid Bergman as Jane, and Olivia de Havilland supposedly considered starring in the project.
Government officials initially resisted director David Lean's request to allow his crew to film on location during the summer months, the height of the tourist season, especially when local gondolieri, fearful they would lose income, threatened to strike if he was given permission to do so. The problem was resolved when United Artists made a generous donation to the fund established to finance the restoration of St Mark's Basilica. Lean also was required to promise the cardinal no short dresses or bare arms would be seen in and around the city's holy sites.
In one scene, the character of Jane Hudson falls into a canal when she steps backward while photographing Di Rossi's shop in Campo San Barnaba. Leading lady Katharine Hepburn, concerned about her health, was disinclined to do the stunt herself, but Lean felt it would be obvious if he replaced her with a double. He filled the water with a disinfectant that caused it to foam, which added to Hepburn's reluctance, then required her to film the scene four times until he was satisfied with the results. That night, Hepburn's eyes began to itch and tear. She eventually was diagnosed with a rare form of conjunctivitis that plagued her for the remainder of her life.
Upon seeing the completed film, Production Code Administration head Geoffrey Shurlock notified United Artists executives the film would not be approved because of its depiction of adultery. Of particular concern was the scene in which Jane and Renato consummate their relationship. Eighteen feet of footage was deleted, and the PCA granted its approval. The National Catholic Legion of Decency, however, objected to a line of dialogue that finally was trimmed, and the organization bestowed the film with a B rating, designating the film "morally objectionable in part."
In later years, Lean described the film as his favourite. He became so enamoured with Venice during filming he made it his second home.
The Academy Film Archive preserved Summertime in 2008.Katharine Hepburn as Jane Hudson
Rossano Brazzi as Renato de Rossi
Isa Miranda as Signora Fiorini
Darren McGavin as Eddie Yaeger
Mari Aldon as Phyl Yaeger
Jane Rose as Mrs. McIlhenny (Rose was the only cast member of the Broadway production to appear in the movie)
MacDonald Parke as Mr. McIlhenny
Gaetano Autiero as Mauro
Gino Cavalieri as Porter at the station (uncredited)
Bosley Crowther of the New York Times observed, "In adapting for the screen Arthur Laurents' stage play The Time of the Cuckoo, Mr. Lean and H. E. Bates discarded most of the individual shadings and psychological subtleties of that romance. They reduced the complicated pondering of an American woman's first go at love with a middle-aged merchant of Venice to pleasingly elemental terms. And they let the evident inspiration for their heroine's emotional release be little more than the spell cast by the city upon her fitful and lonely state of mind. The challenge thus set of making Venice the moving force in propelling the play has been met by Mr. Lean as the director with magnificent feeling and skill. Through the lens of his color camera, the wondrous city of spectacles and moods becomes a rich and exciting organism that fairly takes command of the screen. And the curious hypnotic fascination of that labyrinthine place beside the sea is brilliantly conveyed to the viewer as the impulse for the character's passing moods . . . It is Venice itself that gives the flavor and the emotional stimulation to this film. For it can't be denied that the credibility of the brief love affair . . . is considerably strained in substance. Nor can it be honestly gainsaid that the break-up after a blissful go-round is abrupt and illogical."
Variety said the film "stacks up as promising entertainment - with some reservations. There is a lack of cohesion and some abruptness in plot transition without a too-clear buildup. Lesser characterizations, too, are on the sketchy side . . . Rossano Brazzi . . . scores a triumph of charm and reserve. Hepburn turns in a feverish acting chore of proud loneliness."
Laura Bushell of Channel 4 rated the film four out of five stars and commented, "Hepburn made a career out of playing vibrant heroines with a vulnerable side and it's her portrayal of Jane's insecurity and loneliness that give the film its substance . . . Summertime's notions of dating etiquette and holiday romance have dated greatly . . . but as a coming-of-age story it remains touching. As a showcase for Katharine Hepburn, it is superb."
The film was nominated for the BAFTA Award for Best Film from any Source but lost to Richard III.
David Lean won the New York Film Critics Circle Award for Best Director and was nominated for the Academy Award for Best Director but lost to Delbert Mann for Marty. Katharine Hepburn was nominated for the Academy Award for Best Actress but lost to Anna Magnani in The Rose Tattoo. She also was nominated for the BAFTA Award for Best Foreign Actress but lost to Betsy Blair in Marty.
In 2002 the American Film Institute nominated the film for AFI's 100 Years...100 Passions.
In the anime based on Naoki Urasawa's manga Monster, Anna Liebert's employer Mr. Roso states the film as one of his favorites and always cries when it's on. In addition, he talks about the beauty of Venice and its soundtrack as major influences in his life.
In the TV series Call the Midwife episode "Episode 1" of series 2, the midwives Jenny, Chummy, Cynthia and Trixie attended the theatre where they watch 'Summertime' for Jenny's birthday.