It’s fine to store Christmas lights in a garage as long as it’s dry,” says McDonough. Just be sure to protect them from rodent damage with a lidded storage box - mice like to chew through wires - and check on them throughout the year. It may be best to hang them up in the garage to reduce the possibility of damage from moisture or pests on the ground.
McDonough advises against keeping your Christmas lights in a shed though. “Sheds are usually unheated and uninsulated, so, they can be subject to moisture. They can also get very cold during the winter and hot in the summer throughout the year, so they’re not always ideal for storing Christmas lights.