With the sweltering heat of summer, who wants to cook or even think about cooking? Even with great air-conditioning, cooking still generates extra heat for the AC to process, not to mention how uncomfortable the cook is in the kitchen. Few even want to go outside long enough to barbecue.
There is always the reliable microwave but a cold supper just sounds so much more refreshing (and easy). There are of course there are the old standbys for a cold supper: