Some websites incorrectly report that Linda Lavin and Van Johnson were replacements in the roles of Daisy Gamble/Melinda and Dr. Mark Bruckner. They did star together in a short tour of the show, but neither Lavin nor Johnson was ever in the show on Broadway.
Lavin was in It's a Bird ... It's a Plane ... It's Superman when On a Clear Day closed. She'd gone into Superman directly from The Mad Show, which had opened in January 1966 and which she'd left very shortly after the opening in order to join Superman.
All ads that we can find from different points during the On a Clear Day run display Barbara Harris and John Cullum as the stars, including the ABCs in the New York Times on June 11, 1966 (the day of the production's closing). Several days before the closing, there was a small article in the Times stating that Johnson would be starring in a tour of the show.
Somewhat surprisingly, an article in the Times on June 13, 1966, stated that other commitments would prevent Van Johnson from starring in the tour, but he did star in the tour, which shut down quickly when the tour's producer declared bankruptcy.
Another tour, starring Howard Keel and Barbara Lang, was sent out eight months later.
Some sources, including The Best Plays of 1965-1966, incorrectly list Evelyn Page as having played Mrs. Hatch in the opening-night cast. On opening night, Rae Allen played the role. Evelyn Page replaced her shortly into the run.
Edward Jablonski's biography of Alan Jay Lerner states that John Cullum was a member of the show's chorus when he was chosen to replace Louis Jourdan during the tryout run in Boston. Some websites have picked up this incorrect information. Cullum was not in the show prior to taking over the role that Jourdan had been playing, Dr. Mark Bruckner, nor was he the standby for the role. Hal Linden was the standby for both Jourdan as Mark Bruckner and for Clifford David as Edward Moncrieff, and this was the case from the beginning.
The opening-night playbill's list of musical numbers seems not to have completely reflected what was performed on opening night. Our main list of musical numbers for the production comes from a playbill with a revised list from shortly after the opening.
The roles of Bob Brody and Jimmy Dern were cut shortly after opening night. It's even possible that they were gone by opening night, altough they were listed in the opening night playbill.
In William Daniels's memoir, There I Go Again: How I Came to Be Mr. Feeny, John Adams, Dr. Craig, KIITT, & Many Others, he seems to say that he left this show during the run, but as far as we can tell, he was in the show till the closing performance. It may be that he had turned in his notice, but the show closed before he was to leave.
Composer Burton Lane won a 1966 Grammy for the score in the category then called (according to the report in Variety on the 1966 awards) “Best Score From an Original Cast Show Album (Composer's Award).” According to the issue of Billboard dated October 23, 1965, the dates of eligibilty for the 1966 awards were November 30, 1964, through November 1, 1965. According to Billboard, “The National Association of Recording Arts and Sciences will present its annual Grammy Awards on March 15 next year, a month earlier than usual. Cut-off date for record eligibily has been changed from Nov. 30 to Nov. 1.”
The other nominees were Bajour (Walter Marks), Baker Street (Marian Grudeff, Raymond Jessel), Do I Hear a Waltz? (Richard Rodgers), and Half a Sixpence (David Heneker).
