Stars like Lily James and Jada Pinkett Smith wasted no time switching into summer mode this week, opting for light, effortless, elegant looks that make soaring heat seem almost OK. Meanwhile, celebs like Elizabeth Olsen and Kim K. went in other directions: too much black fabric and — in the case of the latter — not nearly enough.

Jada Pinkett Smith

Flip-flops? Hell no! While in Miami promoting her latest film, “Magic Mike XXL,” the actress raised the standard for summer dressing in this strapless Ermanno Scervino dress, which was topped off with a proper pair of Alaïa sandals.

Erin O’Connor

At the Vogue and Ralph Lauren Wimbledon summer cocktail party in London, the statuesque British beauty proved exactly why she’s a supermodel in a backless Ralph Lauren Collection ivory gown.

Lily James

James was also at the Wimbledon fête — and couldn’t have looked lovelier in her Ralph Lauren Collection shirt dress, which came with a literal twist.

Rosamund Pike

In China for a “Gone Girl” press conference at the Shanghai International Film Festival, Pike donned her own easy, breezy shirt dress — this one by Erdem and adorned in pretty flowers.

Dascha Polanco

Leopard and floral-print sequins might be acceptable for Gay Pride events in NYC, but from where we’re sitting, the “Orange Is the New Black” actress would have been better off wearing her saggy beige jumpsuit.

Elizabeth Olsen

So she read “ ‘Avengers: Age of Ultron’ Tokyo premiere” and thought “Victorian mourning mullet gown”? Get it together, Lizzy — the words “Olsen” and “bad” don’t belong in the same sentence.

Michelle Williams

OK, it’s the Style Africa Gala in LA, where flaunting bold colors and prints is totally cool. But those Destiny’s Child days are done, Michelle — you don’t have to wear the “ugly” outfit anymore.

Kim Kardashian West

We all know Kim is the No. 1 disciple of the cult of her own curves, so it’s safe to say no one expects her to wear a muumuu for nine months. Still, for a nice party in Cannes, couldn’t she at least try to be not so predictable? This sheer shock tactic is now ineffective and old.