When Katharine Hepburn filmed the scene where she falls into the canal, one of her eyes became infected. That infection stayed with her for the rest of her life.
Katharine Hepburn was more than impressed with her experience working with director Sir David Lean. She even asked to sit in on the editing sessions with him to watch him at work. In her autobiography, she wrote, "(Summertime) was told with great simplicity in the streets, in the Piazza San Marco. We would shoot in tiny streets only a few feet wide. The sun would come and go in a matter of minutes. It was a very emotional part, and I tell you I had to be on my toes to give David enough of what he wanted practically on call. But it was thrilling... He seemed to me to simply absorb Venice. It was his. He had a real photographic gift. He thought in a descriptive way. His shots tell the story. He was capable of a sort of super concentration. It made a very deep and definite impression on me, and he was one of the most interesting directors I ever worked with. Wasn't I lucky to work with him?"
Having cast Isa Miranda as the older widowed concierge of the hotel, director Sir David Lean was upset to find that she had recently had a facelift and looked too young for the part. Since recasting at that late stage was out of the question, Lean went with it.
The number of tourists travelling to Venice doubled after this movie's release.