Not exactly sure what happened but have some thoughts on it. You didn't indicate if it was older leaves, newer leaves or a combination of both. Since you just bought them, it is possible that the foliage was not 'hardened off' and not ready for outdoor condtions. This would especially be true of the new leaves. While it may have been 60 degrees (which in itself wouldn't be damaging), any strong winds could've desiccated the tender growth. While they like bright light, they adapt well to lower light levels. Depending on when you bought them, and where you had them inside, taking them out into the bright sun could've caused the symptoms as well - along with any moisture issues and the wind. You are correct in cutting off the damaged leaves. As for watering, they don't like to be over-watered and are often good indicators when they need it - they wilt down. Peace lilies are also very sensitive to fluoride in water. The damage appears as brown tips. There's not much you can do for this unless you switch to rainwater or some water source other than municipal.