These Lightweight Dresses Will Keep You Comfortable Amid Summer Heatwaves—and They’re All Under $40

Lightweight sundresses are the unofficial uniform of summer, and right now Amazon has dozens of breathable options under $40 to shop. With flowy and airy fits, versatile styles, and lengths perfect for layering, now’s the time to stock up on seasonal staples that’ll make the heat wave more bearable (and fashionable!). 

We scoured Amazon’s sale for dresses that are cute enough for brunch and comfy enough for the beach, landing on cool and casual designs that won’t break the bank. From a trendy denim overall dress ($37) to a ruffle-sleeved frock ($17), here are 12 fits worth adding to your closet. 

Best Lightweight Dresses Under $40 at Amazon

• Ofeefan Ruffle Short-Sleeve V-Neck Shift Dress, $17 (was $37)
• Grecerelle Round Neck Maxi Vacation Dress, $29 
• Bzb Denim Crewneck Jean Denim Overall Dress, $37 (was $46)
• Athlisan Casual V-Neck Sundress, $28 (was $34)
• Anrabess Sleeveless Smocked Back Tank Midi Dress, $39
• Yiulangde Smocked Halter Maxi Dress, $37
• Kirundo Flowy A-Line Vacation Dress, $26 (was $36)
• Zaberry Floral Sundress, $38 (was $43)
• ChicGal Strapless Floral Sundress, $15 (was $19)
• Floerns Plus Size Eyelet Embroidery Flared Cami Dress, $37 

Ofeefan Ruffle Short Sleeve V-Neck Shift Dress

This versatile shift dress seamlessly transitions from farmers markets to date nights with its relaxed fit, stretchy material, and subtly sweet ruffle sleeves. Pair it with sneakers for errands around town and jazz it up with kitten heels for an evening out. The dress even has thoughtful front pockets for stashing goods on the go. 

Shoppers appreciate the frock’s flattering drape, true-to-size feel, and lightweight softness. According to one five-star reviewer, who called the dress “fashion-forward and comfortable,” the style is “perfect for summer outings, trips to the grocery store, or dinner under the stars.” Try it on for yourself for under $20 today in over 20 different colorways.  

Grecerelle Round Neck Maxi Vacation Dress

If you’re headed somewhere hot this summer, this functional dress can help keep you cool and protected from the sun. Its maxi length, shoulder-covering cap sleeves, and high-neck design work to block UV rays while breathable fabrics keep air circulating. The dress features handy pockets, a modest side slit hem, and an underarm “anti-flash” patch to avoid exposure. Plus, it's great for travelers, thanks to its wrinkle-resistant and machine-washable materials (one frequent flyer called the maxi “so comfy” for long plane rides and their “go-to-travel dress”).   

Customers praise the Grecerelle Vacation Dress for its size offerings that range from XS to 3XL, as well as its 40+ color options that include both muted neutrals and bold patterns. With over 1,300 five-star reviews, there’s plenty to love about this holiday staple. Grab it now in your favorite shade for $29. 

Bzb Denim Crewneck Jean Denim Overall Dress

Enjoy classic comfort with this deceptively soft denim dress. Constructed from 85% cotton and 15% polyester, it has the perfect balance of stretch and structure for hot days and layering. Pair the mini dress with a white tee and tennis shoes for the perfect summer fit, or transition it during the fall with a long-sleeve undershirt and boots. 

Hundreds of Amazon shoppers give this overall dress a perfect rating for its easy-to-wear silhouette, on-trend design, and practical pockets, saying that it holds up well in the washing machine and doesn’t shrink after multiple wears. The dress is 20% off as part of a limited promotion—so shop your size before time (or inventory) runs out. 

There’s more lightweight dress deals to explore at Amazon right now, including a gorgeous halter-top maxi dress that makes the perfect plus-one fit for a wedding and a casual floral pull-on under $20. All picks are shopper-beloved and under $40; scroll on to check out more top deals. 

Athlisan Casual V-Neck Sundress

Anrabess Sleeveless Smocked Back Tank Midi Dress

Yiulangde Smocked Halter Maxi Dress

Kirundo Flowy A-Line Vacation Dress

Zaberry Floral Sundress

ChicGal Strapless Floral Sundress

Floerns Plus Size Eyelet Embroidery Flared Cami Dress

Merokeety Waffle Knit Drawstring Tank Dress

Zeagoo Short Sleeve Button-Down Shirt Dress