On working with Jane Fonda, Angela Lansbury would recall: "I went to her room while we were on-location and attempted a friendship, but Jane, at that time, was into the Method. She wasn't friendly with me [in character] on-camera so she wasn't going to be friendly with me off. There's a time for that, I think, and there's a time to just let acting be acting."
The first candidates for the roles eventually played by Peter Finch, Jane Fonda, Angela Lansbury and Arthur Hill were Richard Burton, Audrey Hepburn, Carolyn Jones and Stuart Whitman.
Jane Fonda would on "Watch What Happens Live With Andy Cohen" recall ''In the Cool of the Day'' as the worst movie of her career, so bad she suspected (incorrectly) that it had been denied theatrical release and definitely a film which should never been made. Ironically, Fonda had been eager to star in ''In the Cool of the Day''; to fit its shoot into her schedule had necessitated a "rushed wrap" on her preceding film L'école des jeunes mariés (1962) and the postponement of her upcoming Broadway show ''The Fun Couple.'' Fonda's initial enthusiasm was at least partly due to her involvement with Greek actor Andréas Voutsinas, the location shoot in Greece to serve as a romantic vacation and the chance for Fonda to meet Voutsinas' family. After Voutsinas opted not to accompany Fonda to Greece - theoretically he would have been drafted into the Hellenic Armed Forces on arrival - Fonda asked John Houseman to release her from the film (he wouldn't).
Within a few months of this movie's release, Peter Finch would express deep regret at having agreed to be in it, adding that John Houseman had admitted only reluctantly producing ''In the Cool of the Day'' in order to complete his contractual obligations to MGM.
Lawrence Durrell, mentioned by Frederick Bonner (Alexander Knox), was noted for his travel writing about Greece and the Mediterranean, including the books "Bitter Lemons" and "The Greek Islands." He was best known for his novels in the Alexandria Quartet.