Most people probably associate the idea of a Spanish wine-based summer drink with Sangría, but actually that's just for tourists. What Spaniards really drink in summer is Tinto de Verano (Summer Wine).
Put a load of ice cubes into a jug. Add the wine, vermouth, and lemonade or Casera. Give it a good stir, add a couple of orange wedges and serve over more ice with a slice of orange and possibly a little paper umbrella.