I'm a big fan of salad, pasta salad and fruit salads during the summer.
Insalada caprese pasta salad - add fresh tomatoes, fresh mozzarella, basil, olive oil, s&p to cooked, drained pasta of choice. Watermelon, feta cheese, nicoise olives, & balsamic. Tomato, cucumber, red onion salad - add cooked cooled pasta, oil & vinegar. Antipasta pasta salad - black olives, chunks of mozzarella, or fresh grated parmesan, slices of salami, sun-dried tomatoes, Italian dressing - mixed with biow tie pasta.
When it's too hot to turn on the oven, pick up a rotisserie chicken, remove the skin and shred in bite-sized pieces and make chicken salad - add ins - sliced avocados, strawberries, mixed greens, grapes, walnuts - or a grilled chicken salad. Chinese chicken salad, nicoise pasta salad, panzanella -- add grilled asparagus, cukes, tomatoes, red onions, kalamatas, capers, red wine vinegar & olive oil, S&P.
Cold soups - cucumber, peach, gazpacho
Seafood salads - cooked bay shrimp &/or crab meat, sliced hard boiled eggs, cherry tomatoes, sliced avocado, lemon wedges on mixed greens with Thousand Island dressing.
Anything on the grill - Shish kebob - chicken, beef, shrimp - thread with veggies of choice - i.e. mushrooms, onions, etc & serve w rice. Ribs come out fall-off-the bone good in a CP, if you don't have a grill & it's too hot to cook.
A picnic meal I like - rotisserie chicken, tomato pie (posted on this site) cold macaroni or potato salad, coleslaw, a green salad & Sangria. Well, that's for starters
I'm sure I'll think of some more later.