A while back I’d heard of a fabric called “double gauze” that was supposedly perfect for hot weather, but at the time it was really only available imported from Japanese shops and really expensive at that! Fast forward a few years and it’s now much more readily available locally, so when I was in Brighton last August I bought some of their muted teal double gauze fabric (also available in a bunch of other colours), keen to try it out. Double gauze is two layers of cotton gauze/muslin fabric joined together with stitches in a grid pattern which creates a sort of seeersucker or quilted texture. It also means the two layers may not be 100% on grain to each other, and it really likes to shrink in the wash so be sure to pre-wash it.
I wasn’t quite sure what to do with it though until I saw the perfect day dress in the May 2019 edition of KnipMode magazine (#11, though #12 is a longer version with longer sleeves). The pattern is available to buy online, too, though be aware the instructions are in Dutch.