"They just decided they would leave today," he said.
The Clintons are scheduled to land at Andrews Air Force Base at 10 p.m. ET on Monday.
Mr. Clinton arrived in Park City on Saturday to join his wife Hillary and daughter Chelsea for a ski weekend.
Chelsea, who turned 19 on Saturday, was scheduled to return to school at Stanford University on Monday, The president and his wife were to have remained until Tuesday, but decided to come back Monday to get a head start on a busy week.
As they did last year, the Clintons spent the weekend at the gated multimillion-dollar home of of Hollywood producer Jeffrey Katzenberg, who lent them his estate.
Katzenberg, co-partner with Steven Spielberg and David Geffen in DreamWorks SKG, is a big campaign donor to Mr. Clinton and other Democrats. The former Walt Disney Co. studio chief is a frequent guest at the White House and Mr. Clinton has stayed at his Malibu, Calif., home.
Mr. Clinton told reporters en route to Park City from a fund-raising visit to Los Angeles that he was looking forward to a long weekend of reading with no bigger plans than perhaps a trip into town for coffee.
The Clintons had a private dinner for Chelsea on Saturday as she turned 19. It was the second straight year they have celebrated her birthday in Park City.
The first lady and Chelsea were spotted on the slopes Sunday by photographers and cameramen. Mrs. Clinton was overheard expressing irritation to Secret Service agents about someone who had skied too close to her.
Mr. Clinton does not ski. He tried it once 15 years ago in Sun Valley, Idaho, where he took repeated tumbles and finished the day with torn ligaments in his left knee.
Written by Kevin Galvin