Not all cotton is created equal and lightweight cotton breathes differently than heavier weight. Lightweight cotton moves easily and does not cling in humidity which solves the primary problem of summer dresses. The fabric also packs down small for travel which makes it genuinely useful. Lightweight does not mean cheap because quality lightweight cotton has structure and weight without bulk. These work for every season actually because they are breathable in summer and layer easily in cooler months. The lightness also means the dress drapes beautifully on different body types. These are the lightweight cotton dresses that work because the fabric weight makes them genuinely wearable in actual heat.