The natural sweetness of the watermelon combined with the sweetness of the raspberries and sour lime will create a light refreshing drink to keep you company poolside.
In a blender (I use my NutriBullet), blend together all ingredients until smooth. Depending on the sweetness of the watermelon, you may need to add a tad bit more sugar until sweetness it at your desired taste.
Pour in chilled glass cup or bottle and serve immediately