September can be a sartorially confusing time of year, when you don’t know whether you should be stepping out of the house in a slip dress or embracing leather jacket season. The temperature is turbulent, climate capricious! But as tricky as the transitional season is, this week’s best dressed stars were up for the challenge: Hollywood’s finest balanced both summer and fall dressing, serving up a healthy mix of easy-breezy dresses and sleek suits.

Naturally, many of the standout style moments this week came out of Venice, where the annual film festival is in full swing. For more summery moments, stars like Amal Clooney stepped out in Stella McCartney’s raspberry-toned, dotted-print frock; model Bhavitha Mandava also produced one of the most glamorous evening moments in her aqua-blue Chanel gown with sequined scales that made her look like a real-life mermaid.

But just when you thought all of the looks were about dresses and gowns, other stars veered more into fall territory with their tailored jackets and suits. In Paris, Celine Dion slipped into a satiny blazer from Givenchy’s Sarah Burton, paired with jeans for a cooler finish. Jennifer Lawrence also attended the LVMH Prize event in a tailored Dior two-piece suit.

The best serve of the week, though? That would go to Naomi Osaka at the U.S. Open, when the tennis pro wore a custom Thom Browne design for her walk out onto the court. You could say it was a total fashion smash.

Which were your favorite celebrity looks this week? Vote below, and check back on Friday to see who Vogue readers crowned best dressed.