For the melonade, scoop out the flesh of the watermelon and cut it into small pieces. It is best to cut the watermelon over a bowl, so you can immediately collect the melon water and add it later to the lemonade.
Place the melon pieces and lime juice in a blender or blender. Blend until all the melon pieces are chopped. Pour the melon juice through a fine hair strainer into a pitcher.
Stir the brown sugar into the melon juice. Before serving, pour the melonade with ice-cold tap water or mineral water and serve with ice cubes.