A:AnswerNot unless your Christmas lights are USB. The wall plug is made as a input for the device. I do not believe there is enough wattage for this to run them for any amount of time even if it would. I would look at a standard UPS like this if you are set on not using an extension cord from inside:
https://www.bestbuy.com/site/apc-back-ups-pro-1000va-battery-back-up-system-black/6070800.p?skuId=6070800
Just charge it up full then unplug it and use it outside. Make sure it is protected from the weather and moisture as the really are not made for outdoors.
