But despite the sunshine, and the company of financier Jay Barrymore, the Harry Potter actress had a permanent face like thunder.
Perhaps she had been having difficulty explaining why she was pictured recently enjoying an evening out in New York with a fellow student who happens to be a glamorous Spanish rock star.
Miss Watson, 19, is taking a degree in art and literature at Brown University, an Ivy League institution in Providence, Rhode Island, while 26-year-old Mr Barrymore remains in London.
Given a five-day break for the Thanksgiving holiday, she met him in Jamaica at the weekend for what many observers felt could prove to be 'make or break' for the couple's 18-month relationship.
Judging by her expression, the smart money is on 'break'.
The actress, who has built up a fortune of more than £10million playing Hermione Granger in the Potter films, began her degree course two months ago.
Last week, the Daily Mail pictured her smiling at an ice-hockey match with Rafael Cebrian, a second-year student who plays in a Spanish band called the Monomes.