William Hurt and Kathleen Turner wanted the crew to feel comfortable filming their love scenes, so they lined up the crew and both actors introduced themselves to each crew member. When they did this, both stars were naked.
Christopher Reeve was offered the lead but turned it down after saying, "I didn't think I would be convincing as a seedy lawyer."
Director Lawrence Kasdan wanted unknowns to star in the film so there would be a sense of discovery as if they were real.
Reportedly, the picture was shot in freezing cold temperatures. The production had to simulate the heatwave of the film's story, the actors having to act hot in cold conditions. For example, the cast had to suck ice cubes before speaking to eliminate foggy breath and had water sprayed on their skin and clothing to simulate perspiration. Kim Zimmer's memoir disputes this. She remembers shooting in blazing heat and high humidity.