This Under-£100 Dress Is the Answer to Looking Polished in the Heatwave

I don’t know if you’ve heard, but there’s a heatwave coming. In fact, as I sit here writing this with my face as close to a fan as possible without my hair getting dragged in, I’m pretty sure it’s already arrived. Temperatures will be reaching crazy highs next week (does anyone remember a time when the UK was 35°? Me neither), but it also looks set to be really warm throughout the whole month of July and likely into August and September, too. Better late than never, I guess?
I’m not complaining. In fact, I’m very grateful for the rising temperatures after summer never really arrived last year. It’s lovely weather for sitting in the garden and doing nothing. The problem arises when we’re expected to leave the house and still look polished. Whether you’re going to the office, a meeting, a date, or drinks with friends, not looking like you’ve just left a hot yoga class feels like a challenge equivalent to climbing Mount Everest. So what the heck do you wear to stay cool but also appropriately covered up?
Well, that last part I can help you with. I’m not great in the heat, and so I’ve been scrolling through my go-to summer brands this week to find pieces that are not only heatwave-appropriate but also office-appropriate. These are pieces that I can wear comfortably over the next few weeks but that I know I’ll want to pull out when the mercury rises next summer as well. I’m a sucker for a good investment, after all. Obviously, my first thought was to find something linen, which, as we all know, is the true secret to looking chic in the heat. And when I came across COS’s Linen Shirt Dress (pictured above), I knew I wouldn’t find anything better.
The under-£100 dress is a short-sleeved, floaty, throw-on, button-down midi dress that comes in three colours: white (ideal for heatwaves and beach days), navy (very French), classic black and a soft lilac for the colour fans amongst us. The natural linen won’t stick to your back or show sweat patches, and it won’t make you hotter than you already are. Plus, the midi length keeps it feeling elevated and suitable for all sorts of occasions. Dress it up with heeled sandals or dress it down with classic leather slides or Birkenstocks. It even works with trainers and a trench coat or over trousers as we head into autumn. What more could you really ask for in a dress?
Keep scrolling to shop the dress, and see more of my heatwave shopping picks below.
Shop COS's Relaxed Linen Shirt Dress
Shop More Under-£100 Heatwave Dresses
Up Next: 24 Heatwave-Proof Dresses That Come in Under £100

Emily Dawes is an editor, stylist and writer with over 12 years in the industry. Known for impeccable taste, our readers trust her advice, especially in her column, expensive-looking high street buys. Working forBest Knockoff Luxury Clothing UK since 2020, Emily has been a contributing editor, branded content editor and affiliate editor. Now, as senior shopping editor, she leads the e-commerce content strategy. After obtaining a BA in English and American Studies from Nottingham University, Emily landed at The Mail on Sunday’s YOU. As the magazine’s fashion editor, she travelled the globe to style and direct fashion editorials and celebrity cover shoots. As a freelancer, she has styled Grazia cover shoots, developed brand marketing and content plans and worked with VIP clients including Elizabeth Day.
-
Holy Ref! Holier COS! These 27 Finds Just Got Me So Excited for Fall (Sorry, Summer—I'm Over You)
These buys plus a Gilmore Girls rewatch.
-
I Accidentally Started a Capsule Wardrobe When I Added These COS, Madewell, and J.Crew Items Into My Closet
And I got rid of all the pieces that couldn't compete.
-
I Haven't Worn a Dress in a Year, But These 37 From Reformation Are Making Me Want to Change That
Just slip these on.
-
These 31 Effortless Summer Basics Make Getting Ready So Much Easier
Low lift, high reward.
-
Forget Trying Hard—This Dress Trend Is Every Stylish Woman's Secret to No-Effort Dressing
Putting together an outfit has literally never been easier.
-
Forget Burgundy—COS Has Declared *This* the It Color to Wear for Fall
It's lighter and more romantic.
-
If You're Anti-Jeans, TheseReplica Store Skirts, Dresses, and Pants Will Make You Giddy
Stylish bottoms to the front!
-
5 Shirt Trends Everyone in NYC Is Wearing With Trousers and Jeans
Make your next outfit more interesting.