Bouncy castles are a lot of fun, but they're not meant to be left up overnight. Inflatable bouncy castles are made of PVC or other heavy-duty materials that can withstand a lot of wear and tear, but they're not designed to be left out in the elements for extended periods of time.nnUV rays from the sun can cause the material to degrade over time, and strong winds can damage the structure. If you leave a bouncy castle up overnight, it's likely that it will be damaged by the morning. So if you want to enjoy your bouncy castle for longer, make sure to take it down at the end of the day.