Breathability becomes the spec. From 20°C, the question flips: not how to keep heat in, but how to let it out. Weave matters more than weight — linen and open-weave cotton move air through the fabric; a dense synthetic tee the same thickness will sit on you like cling film. Read the fibre before the style: at 23°C, a linen overshirt is cooler than a thin polyester blend, counter-intuitive as that looks on the hanger.
One layer means every piece is on show. With no jacket to pull an outfit together, the two or three pieces you wear carry all of it. This is where camp-collar shirts, well-cut polos and interesting trousers pay off — and where a tired tee has nowhere to hide. Fit does the work insulation used to: a slightly relaxed cut lets air circulate and reads more composed in heat than anything clinging.
Bare legs earn their place; the options open right up. Above 21–22°C is where a dress or skirt comes into its own worn bare-legged — a slip dress, an easy summer dress, a skirt with a tee — and where tailored shorts with a proper shirt become a legitimate outfit rather than a concession. Light trousers — linen, seersucker, airy cotton — still hold their ground, feeling just as cool while giving sun protection and covering the smarter end of the day. The old split does most of the sorting: shorts, skirts and throw-on dresses for daytime errands and leisure, light trousers or a longer dress for evening and anything with a dress code.
Feet and sun round it out. Canvas trainers, loafers without socks (or with invisible ones), and leather sandals at the casual end all suit the band. From here up, a cap and sunglasses shift from accessories to equipment — UV at 24°C in June is fiercer than most people credit. Light colours help twice: they reflect sun and hide none of their sins, so this is the moment whites and creams leave the wardrobe.
Carry one thing for the evening drop. A 24°C day can hand you an 17°C terrace by ten o'clock. A light knit or an overshirt, rolled into a bag and forgotten until needed, is the difference between staying out and heading home. Sweat is now the main thing your clothes absorb, so rotate and wash light layers more often than you would in winter — cotton and linen both take frequent washing happily.
